METHOD AND APPARATUS FOR CONTROLLED REHABILITATION AND TRAINING OF MUSCULAR SYSTEM
A system and method for controlling an exercise in an apparatus for training and measuring muscle strength. The system includes an apparatus with moving means actuated by force applied by a user, a magnetorheological brake unit resisting the movement of the moving means moved by user force applied, a control unit actively controlling the resistance of the magnetorheological brake unit during the exercise on the basis of a sensor signal from one or more sensors, one or more sensors measuring the behavior of the moving means, and a processing unit connected to the control unit for selecting parameters of an exercise.
This application is a continuation of PCT/FI2014/050174 filed Mar. 10, 2014, which claims priority from Finnish Patent Application No. 20135230 filed Mar. 11, 2013, the entire disclosure of each of which is incorporated herein by reference.
FIELD OF THE INVENTIONThe invention is concerned with a system and an apparatus for controlled exercise, and a method for controlling exercise in an apparatus for controlled exercise.
BACKGROUNDPhysical activity and a good physical condition play a major role both among employees and the growing group of elderly people in prevention and treatment of chronic diseases as well as in maintaining adequate functional capacity for work and daily living.
Muscle strength and endurance is an important part of physical condition. When properly performed, strength training can provide significant functional benefits and improvement in overall health and well-being even for elderly people. Especially, the muscle strength of the legs directly affects the balance and prevents falling and injuries. Research evidence indicates that even intensive strength training can be safe and beneficial for senior people.
Nowadays, a great deal of emphasis is on the safety and versatility of measuring and training equipment. The role of modern technology and intelligent solutions has remarkably increased recently. Measurement of the initial muscle strength to determine the proper training intensity and using the same technology for the training itself significantly improves the safety and success of the training program.
Training commonly uses a technique for progressively increasing the force output of the muscle through incremental weight increases and uses a variety of exercises and types of equipment to target specific muscle groups.
Traditionally, strength exercise has been associated with the lifting of free weights consisting of plates of e.g. steel, positioned on a bar, which resist a force applied by a user through the action of gravity. There are exercise apparatuses for different muscles, such as for arms, legs, shoulders, etc.
An example of such an exercise apparatus is the leg press. One type consists of a diagonal sled-type leg press machine. Weight disks (or plates) are attached directly to the sled, which is mounted on rails. The user sits below the sled and pushes it upward with the feet. These leg presses normally include adjustable safety brackets that prevent the user from being trapped under the weight. The other type, the sc. cable type leg press, or seated leg press, is commonly found in gyms. The user sits upright and pushes forward with the feet onto a plate that is attached to the weight stack by means of a long steel cable.
In addition to the free-weight form of exercise, other exercise apparatuses are designed to replicate other particular conventional exercise modes, such as rowing or cycling performed on apparatuses resembling real devices but remaining stationary.
Typically, there are four modes of exercise, which a user may perform. These modes may be called isometric, isotonic or isoinertial, isokinetic and cardiovascular modes. The three first mentioned types are commonly anaerobic training by nature, whereas cardiovascular exercise is aerobic.
Control of muscular force output in the body is based on recruitment of motor units that consist of a single motor nerve and a number of muscle cells it innervates. The higher level of force output is needed, the higher amount of motor units will be needed to activate.
There are basically two types of motor units: fast and slow. The slow ones produce lower muscle tension, are fatigue resistant and are recruited when lower level of tension is needed. The muscle cells of the slow motor units produce most of their energy in the presence of oxygen i.e. aerobically. The fast units are able to provide rapidly greater muscular tension and are recruited when greater force output is needed. The muscle cells of fast units produce more of their energy without oxygen i.e. anaerobically and are more fatigable than those of the slow units. Typically, maximal or near maximal muscle exercises lasting less than two minutes are anaerobic by nature.
Isometric exercise is associated with an exercise, in which a user applied force does not result in any range of motion, like when pressing the palms of hands together. Isometric exercise or isometrics are a type of strength training in which the joint angle and muscle length do not change during contraction (compared to concentric or eccentric contractions, called dynamic/isotonic movements). Isometrics are done in static positions, rather than being dynamic through a range of motion.
Isotonic exercise is associated with the mode of exercise in which the resistive force remains constant. An example of such an exercise is the above described free-weight lifting exercises. To be precise, this type of exercise should be called isoinertial, because the tension of the working muscle group changes with the change of joint angle and speed of motion. True isotonic exercise means the same muscle tension throughout the range of motion and would need a device capable of changing the resistance with the range of motion.
There are two types of isotonic (or isoinertial) contractions: (1) concentric and (2) eccentric. In a concentric contraction, the muscle tension rises to meet the resistance, then remaining the same as the muscle shortens. In an eccentric contraction, the muscle lengthens due to the resistance being greater than the force the muscle is producing.
Isokinetic exercise is an exercise associated with a variable force resisting a user applied force along the range of motion of an exercise, so that the velocity along the range of motion of the exercise remains constant.
In practice, there is no isokinetic muscle work in daily living and special dynamometers are required to perform isokinetic exercises. The benefit of isokinetics is that muscle work can be maximally resisted throughout the range of motion. Furthermore based on the research results, it is considered to be the safest form of muscular work.
Cardiovascular exercise (also known as cardio or aerobic exercise) is associated with an exercise in which the heart and blood vessel system, as well as muscle groups and nervous system are caused to experience consistent and relatively prolonged stress.
Aerobic exercise is physical exercise of relatively low intensity that depends primarily on the aerobic energy-generating process. Aerobic refers to the use of oxygen to adequately meet energy demands during exercise via aerobic metabolism. A simple example is jogging, throughout which the heart rate is elevated to supply nutrients and oxygen to the fatiguing muscles.
Aerobic exercise and fitness can be contrasted with the above mentioned anaerobic exercise, of which strength training and short-distance running are the most salient examples. The two types of exercise differ by the duration and intensity of muscular contractions involved, as well as by how energy is generated within the muscle.
In most conditions, anaerobic exercise occurs simultaneously with aerobic exercises because the less efficient anaerobic metabolism must supplement the aerobic system due to energy demands that exceed the aerobic system's capacity.
Different types of exercise are also distinguished by the fact whether they are closed or open kinetic chain exercises.
Closed Kinetic Chain exercises or closed chain exercises (CKC) are considered to be an activity in which the distal component of the extremity is fixed. The fixed end may be either stationary or movable. An example of a CKC exercise in which the distal end is stationary is a squat exercise in which the foot is fixed to the ground. An example of a CKC exercise in which the distal end is movable is an exercise on a leg press system in which the athlete's body is stationary and there is a movable footplate.
The opposite of CKC exercises are Open Kinetic Chain exercises (OKC). An open kinetic chain exercise is considered to be an activity in which the distal component of the extremity is not fixed to an object. One of the best examples of the OKC pattern is performance of a knee flexion-to-extension pattern while sitting.
Closed chain exercises are often considered safer and more functional compared to open chain exercises. Nonetheless, the both ways of exercise are successfully used in rehabilitation and strengthening purposes.
CKC exercises involve more than one muscle group and joint simultaneously rather than concentrating solely on one, as many OKC exercises do (single-joint movements), lending the former to more utilitarian and athletic activities.
There are some health hazards involved in muscle strength training. In isoinertial work, the maximal force output of a certain muscle group take place in a certain muscle group specific joint angle. Thus, there is a risk to tissue overloading and injury. On the other hand applying low resistance may lead to inadequate strength improvement. Isometric muscle contractions cause rapid increase of blood pressure that may be dangerous for people with cardiovascular diseases. These potential risks are proved to be lower within isokinetic exercise.
Most medical isokinetic machines use powerful active dynamometers with electronic servomotors or hydraulic valve systems to provide isometric, isotonic or isokinetic resistance controlling a lever arm in both directions. Thus, usually these machines provide open kinetic chain exercises. The motor resists a pushing force (concentric) and pulls in the opposite direction to the pushing force to give eccentric.
The machines are costly, large at size and therefore stationary. The use of them is time consuming and requires a lot of training and skill. In these devices safety requirements are complicated to apply in practice because these devices produce movement by themselves by active external resistance/power supply. They are developed for testing and training the extremities and mid-torso muscles in the open kinetic chain in athletes, patients, and workers to evaluate physical status, performance, and task demands.
Typically the force applied to a lever or through a cable is measured and then converted to a moment of force by multiplying by the perpendicular distance from the force to the axis of the level.
Technical solutions in these devices are more expensive, complex, and they require more space to use. Also the use of these devices requires more special expertise. Due to these features, the devices are mainly used in research centres and not commonly in every day rehabilitation
Some attempts have been made to solve the problems of prior art.
U.S. Pat. No. 5,762,584 comprise a multiprogrammable exercise apparatus for isometric, isotonic, isokinetic and cardiovascular training that provides a variable resisting force in response to a user applied force. In one solution, the user applied force is resisted by varying the viscosity of an electro-rheological fluid that surrounds plates rotated by the user applied force. Thus, a braking force is applied to actively resist the user applied force. A programmable device is provided which may be used in a variety of exercise modes to provide a resistive force to a user-applied force during a range of motion of a particular exercise.
In order to appropriately control the amount for resistance, detecting means can detect a rotational speed of a rotatable member in the apparatus, an electrical power output, a rotational speed of an electrical generator and/or an applied force. The detecting means produces a detection signal, which is received by controlling means for controlling the applied potential depending on the detection signal.
U.S. Pat. Nos. 5,749,807 and 5,810,696 disclose an exercise apparatus with user actuation components moved by a user and a magnetorheological or an electrorheological fluid brake operatively connected to said components for applying a controllable resistance to movement thereof on the basis of a user selected resistance value thus providing a solution by which the user can control the resistance during the exercise. The apparatus is a stepper, exercise bicycle or a treadmill.
OBJECT OF THE INVENTIONAn object of the invention is an exercise apparatus without an active external resistance mode for controlled rehabilitation and training enabling the user to perform versatile and safe muscular work.
Another object of the invention is a system and method for controlling resistance in an exercise apparatus.
SUMMARY OF THE INVENTIONThe system, apparatus and method of the invention are mainly characterized by the features of the main claims.
The advantageous embodiments of the invention are characterized by the features of the sub claims.
Thus, the invention is concerned with a system for controlling an exercise in an apparatus for training and measuring muscle strength. The system comprises an the apparatus with moving means actuated by force applied by a user, a magnetorheological brake unit resisting the movement of the moving means moved by user force applied, a control unit actively controlling the resistance of the magnetorheological brake unit during the exercise on the basis of a sensor signal from one or more sensors one or more sensors measuring the behavior of the moving means, and a processing unit connected to the control unit for selecting parameters of an exercise.
The invention is also concerned with the exercise apparatus comprised within the system and a method for controlling an exercise in an exercise apparatus.
The method for controlling the exercise in the apparatus comprises feeding user data and parameters of the exercise into a program run by a processing unit connected to the apparatus for controlling the parameters of an exercise to be performed. The force applied by a user on the moving means is measured during the exercise by means of one or more sensors measuring the behavior of the moving means. The resistance of the magnetorheological brake unit during the exercise is controlled on the basis of one or more sensor signals from said sensors.
The invention uses a control system preferably in the form of an embedded system to control the force by which a brake unit resists the force applied by the person using the exercise apparatus. The control enables loading of muscles in a desired way. The linear movement of the moving means in the exercise apparatus caused by the force applied by the user is transferred to a rotational movement and resisted by a brake unit.
The embedded system has means for actively controlling the resistance by feedback control. Feedback control is a control mechanism that uses information from measurements to manipulate or control a variable to achieve the desired result. The variable being controlled is measured and compared with a target value also called set value or desired value. This difference between the actual and desired value is called the error. Feedback control manipulates an input to the system to minimize this error.
The desired output is generally entered into the system through a user interface as can be done in the invention. The output of the system is measured and the difference is calculated. This difference is used to control the system inputs to reduce the error in the system.
The feedback system in the invention is an integrated Proportional-Integral-Derivative, PID, controller and/or a fuzzy logic controller.
A proportional-integral-derivative controller (PID controller) is a generic control loop feedback mechanism (controller) A PID controller can calculate an “error” value as the difference between a measured process variable and a desired setpoint and can therefore be successfully used in the invention. The controller attempts to minimize the error by adjusting the process control inputs.
Fuzzy logic is a form of many-valued logic or probabilistic logic; it deals with reasoning that is approximate rather than fixed and exact.
A magnetorheological brake is used as the brake unit because of its ability to be controlled by low-voltage electronics by only one or two coils by not requiring much power supply. Other valuable properties are its strength properties and insensitivity to contaminants and temperature extremes and it is very compact.
The exercise apparatus can be operated in different exercise modes.
Three different functional modes and two combination modes are mentioned as examples:
1. An isometric mode in which muscle work is created without changing the length of the muscle. The apparatus prevents the movement by keeping the brake so that the user feels it is locked. The brake strives to resist the movement by an equal counterforce. The pulse sensor measures the movement of the bearing unit all the time and gives position information of a plate fastened on the bearing unit to the control device that is responsible of the “locking state” of the brake through a constant current controller.
2. An isotonic mode in which muscle work is created against a constant resistance as the length of the muscle changes. The brake resists the movement with a predetermined resistance (e.g. 200 N) during the whole exercise session while the speed of the movement can change. In other words, the brake resists the movement with the same resistance over the whole movement range. An output result of the apparatus is the production of power as a function of time and limb angle.
3. An isokinetic mode in which muscle work is produced with a constant speed while the resistance is changing along with the change of the length of the muscle, i.e. the power used by the user. The resistance of the brake is controlled by means of signals from force and pulse sensors in accordance with the power produced so that the movement has a constant speed. An output result of the apparatus is the production of power as a function of time and limb angle.
4. A variokinetic (combination) mode in which muscle power is produced in accordance with a varying resistance or alternatively in accordance with a varying movement speed along with a changing mucle length, i.e. the power used by the user.
The resistance of the brake is controlled in relation to the power produced or in relation to the speed of the movement. An output result of the apparatus is the production of power as a function of time and limb angle.
5. A cardiovascular exercise can be performed with the apparatus of the invention by selecting either the isotonic or the isokinetic mode. The resistance of the brake is then set at a value light enough for the user and by performing a sufficient number of repetitions of the movements the performance can be long enough to achieve a sufficient aerobic training.
A magnetorheological brake has been considered to work for the purposes of the invention, which then can be implemented with the control system used. Furthermore, an even and continuous load can be achieved. The reaching of a zero momentum is important for some of to embodiments of the invention, which can be realized with a magnetorehological break. Such a magnetorheological brake unit can also be constructed in a size small enough for the purpose of the invention. Reference is made to the example later on in the text.
By means of the inventive magnetorheological brake designed as a part of the invention, a versatile measurement and training of the production of isotonic, isoinertial, isometric, variokinetic and isokinetic muscle strength can be performed. The apparatus of the invention can be used as an exercise apparatus for developing maximum strength, muscular power and muscular endurance. The extension of the movement can be freely adjusted so that the load can be individually controlled in a desired manner for targeted muscles in a movement in an open or closed kinetic chain.
The exercise apparatus of the invention can be implemented as a leg press as is presented as an example in the claims and in the following detailed description.
The invention can, however, also be implemented in apparatuses applied for performing exercises in an open kinetic chain by using different mechanical movements. Such an exercise apparatus can be a leg extension machine, in which the legs of a sitting user are stretched out. Contrary to conventional leg extension machines, wherein the brake consists of plates that resist a force applied by a user through the action of gravity, the leg extension machines of the invention have the brake unit positioned e.g. below the seat or the back support.
It is possible to adjust the load from almost zero resistance, making the system and apparatus of the invention especially useful for weak and/or hypofunctional people. The resistance of the brake can be adjusted to a desired level both in terms of the load and range of motion with the desired muscle action form, i.e. isometric, isoinertial, isotonic, and isokinetic resistance without an excentric load (the brake resists only in one direction). The invention can successfully be applied for rehabilitation of a sick or injured joint since the load on the joint can be optimally adjusted.
Injuries to the knee are the most common reason for people to visit an orthopedic physician. The structure and stress placed upon the knee make it vulnerable to a variety of injuries and knee pain is among the most commonly encountered orthopedic problems. The present invention is very helpful for using in rehabilitation exercises and also generally for performing exercises, wherein special attention is put on a training that is safe in view of avoiding knee problems. The possibility in the invention to control the knee angle is also generally an advantage since it is a factor for a correctly performed exercise session.
The braking mechanism in the apparatus of the invention enables a smooth and exact adjustability for the resisting force in different applications. Therefore, the use of the apparatus of the invention extends from the training of an individual muscle or muscle group to a versatile training of the whole cardiovascular system. Furthermore, the loading adjusting functions can be connected to the system so that the load can be steered in accordance with biometrical signals (such as heart rate, applied power or other external signals).
The system of the invention is different from other known solutions. The configuration of the apparatus is based on modern digital control technology with fast feedback control together with sophisticated mechanical solutions and contrary to prior solutions it enables exactly repeatable and measurable controlled exercise in any desired way of muscular work. Measurability is an important pre-requisite of successful medical rehabilitation. The resistance of muscular work can also be controlled with externally measured biosignals (such as e.g. Electromyography, (EMG), heart rate, and Electrocardiography, (ECG)).
Concerning the brake, a modular coiling of the magnetic circuit is advantageous. Instead of having a big coil, two or more smaller coils are used to increase flexibility. For safer and more comfortable usage, the response time can be improved with such a modular solution and an optimized response time under 100 ms can be reached.
Manufacturing the brakes with different dimensions and properties allows a wide torque range deployment and enables usage of the brakes in versatile purposes.
In the following, the invention will be described by means of figures and some advantageous embodiments to which the scope of protection, however, is not restricted.
The leg press is an apparatus for weight training in which the training person sits on a movable seat 19 and pushes a weight or resistance, which is
Furthermore, there can be a seat unit tilt (not shown) for varying the inclination of the seat 19. The movement direction of the seat 19 in order to change its inclination is described by reference number 27.
Also the inclination of the footplate 10 can be varied by means of a footplate adjusting mechanism 9. The tilt direction of the footplate 10 is shown by reference number 11.
Reference number 23 describes a foot support.
Reference number 12 describes the back and forth direction of the seat movement. The seat 19 is attached with a seat attachment mechanism 28 on a wire rope 3, on which it moves back and forth. The wire rope 3 extends around a magnethorheological brake unit 5 with a turning wheel 4 (see
The wheel 4 of the brake unit 5 and the turning wheel 25 are on a sufficient distance from each other so that the seat 19 can move between a position, wherein the legs of the person performing the exercise are straight and a position close to the tiltable footplate 10, wherein the legs are bent and can push away the seat from the footplate 10 by straightening the legs.
A bearing unit 26 for the turning wheel 25 is attached to both the turning wheel 25 and a device trunk 6.
The wire rope 3 transfers user energy created by muscular work to the brake unit wheel 4 and the brake unit 5 can resist the movement of the wire rope 3 in a programmable manner in accordance with the invention.
The resistance of the brake unit 5 is controlled by components in an embedded feedback system 15 on the basis of signals from sensors 7, 8 that indirectly measure the performance of the person performing an exercise with the apparatus. Pulse sensor 7 measures the position of the seat 19 and force sensor 8 measures the braking force of the brake unit 5, both of which are dependent on the user behavior, i.e. by which force the user presses on the footplate 10 and/or how fast the seat 19 is moved.
Also the adjusting mechanism 9 for the inclination of the footplate 10 and the adjusting mechanism 22 for the inclination of the back support 22 and optionally an adjusting mechanism for the inclination of the seat 19 are controlled by the components of the embedded system 15.
The brake unit 5 is attached to a horizontal shaft 1 (seen in
The apparatus can have a handle bar so that the person using the apparatus can have support for the hands.
A user that is sitting on a seat 19 can push away the seat 19 to a distance from the footplate 10 by straightening the legs as a result of which the wire rope 3 fastened to the seat 19 moves. The transfer of the user energy from the wire rope 3 to the brake unit 5 causes the turning wheel 4 (presented in
The brake unit 5 is a magnetorheological brake unit 5 in the apparatus and system of the invention and is one of the inventive parts of the invention. The brake resists the movement in one direction, i.e resists the outwards directed rotation of the rotating plates of the brake unit 5 and thus the forward direction of the wire rope 3.
The brake unit 5 consists of a magnetorheological mechanism, the function of which is based on an electromagnetic core consisting of plates and coils and on the properties on a so called magnetoreheological fluid.
A magnetorheological fluid (MR fluid) is a suspension of magnetically soft iron particles in a carrier fluid, usually in a type of an oil, or in water. When subjected to a magnetic field, the fluid greatly increases its apparent viscosity, to the point of becoming a viscoelastic solid. The change of the viscosity is caused by the forming of chains of the particles in the direction of the power field lines. The chains resist a movement in a perpendicular direction.
Importantly, the yield stress of the fluid, when it is in its active state, can be controlled very accurately by varying the magnetic field intensity. The fluid's ability to transmit force can be controlled with an electromagnet, and has been used in the control-based applications of the invention.
As was explained in
The movement of the wire rope 3 is resisted by a magnetorheological brake 5 in an extent controlled during an exercise by components (see
A pulse sensor 7 measures the position of the seat that is fastened on the wire rope 3 and a force sensor 8 measures the speed of the wire rope, which is dependent on the force applied by the person using the apparatus.
The signals from the sensors 7 and 8 are fed to the embedded system 15 for processing the signals and for generation a steering signal to the brake unit 5 in order to control the resistance of the break unit 5, i.e. how much the brake unit 5 shall resist the movement of the wire rope 3.
The embedded system 15 could be connected for example via a Universal Serial Bus (USB) to a computer or other processing unit 18 through which a control card is used via a user interface. The sensors, the brake, the USB bus (or other possible Serial Bus) and the adjusting mechanisms (such as spindle motors) are connected to the control card.
The computer 18 has a database with user data of different users. User data includes e.g. the name of the user and other individual and personal data like the age and birth date, the weight, and length, as well as data associated with training goals and training programs for the users as well as training results. It can also include health and measured biometric data. The parameters of the exercise sessions to be performed by the users can be individually selected and/or programmed on the basis of some or all user data.
Furthermore, the computer holds a program for performing different exercise modes on the apparatus also called operating states. These exercise modes are controlled via components in the embedded system 15.
The program controls the embedded system 15 and converts the signals from the embedded system 15 into an understandable form e.g. as figures, curves and numbers.
Thus, the program has partitions concerning user data, measurements, exercises and feedback.
The functionality of the program is presented in more detail in connection with
In step 5, the operating state (or exercise mode) is selected. The exercise mode can in
A patient based device configuration for the apparatus of the invention is performed in step 10 in accordance with goals for the training for the particular person in question. The configuration can also include an adjustment of the range of movement of the apparatus. The range of movement is expressed by means of a desired knee joint angle of the user, whereby e.g. an angle of 0° means that the leg is straight and 90° that the knee is bent in that extent. The desired range of movement is determined by feeding the allowed threshold values for the angles into the user interface.
Thus, the range of movement is restricted to a lower and an upper limit, within which the use of the apparatus is safe. Mechanical restricting means can be used as additional security mechanisms on the rails of the seat when the capacity of the brake has been exceeded.
The whole range of movement consists of the real measurement and exercise range in the middle and of ramps on both sides. Preferably, only one ramp, i.e. the one in the end of a movement is in use.
The apparatus is with respect to operating mode (also called exercise mode) and with parameters for the exercise to be performed in accordance with said goals. Depending on which exercise mode or operating state was selected in step 5, it is either the resistance of the brake unit, the speed of the seat (or the speed of the wire rope) or the knee angle of the training person that is used as a set point of a certain value to be kept constant or to vary in a programmed way. The adjustable values themselves for e.g. the speed, knee angle or force are selected in accordance with an individual training program of each person. The parameters can thus e.g. decide with which force the brake unit is set to resist the movement of the wire rope. One parameter is e.g. a set point of the resisting force of the brake unit if an isotonic mode is selected. If the isokinetic mode is selected then one parameter is a set point of the speed of the wire rope.
Optionally, there can be up warming modes to be performed before the real exercise modes.
The brake unit is steered by the control unit of the embedded system in accordance with the control of these set points to be described in detail in connection with
One possible goal can also be the isometric mode, in which the brake is controlled to resist the movement with an equal counterforce to the user applied force and in that mode there is no real set point for the resistance of the brake.
Step 11 is the set up for the start of the exercise in accordance with steps 5 and 10.
Step 12 stands for the performance itself as performed by the exercising person. The exercise is followed during the performance and the performance is stored as indicated by step 13. The results of the exercise, such as how much force was used by the user as a function of time, can be seen on the screen of the computer in step 14. The results are analysed and compared with earlier results and goals. A decision is then made in step 15 whether to end the exercise illustrated as step 16 or start again and go back to step 5. The performance parameters may change compared to the foregoing step 5 depending on the analysis of step 14.
The embedded system 15 can be a feedback system principally to be implemented as a Proportional-Integral-Derivative controller (PID controller), which is a control loop feedback mechanism (controller).
A digital controller 14 in the feedback system 15 controls the speed/force set point and has a program to convert the information from the control unit (17) to a form to be used as input to a constant current driver 13. The values themselves for example the speed, knee angle or force to be kept constant, are selected in accordance with the individual training program of each person.
In the invention, the PID controller 15 is used to calculate an “error” value as the difference between a measured force or a measured speed and a desired set point for either of these. The controller attempts to minimize the error by adjusting the process, i.e. the force by which the brake unit resists or the speed of the wire rope, by changing the constant current of the control unit on the basis of the sensor signals.
The embedded system 15 control can also be realized with fuzzy logic. Fuzzy logic is a form of many-valued logic or probabilistic logic dealing with reasoning that is approximate rather than fixed and exact.
A control unit 17 in the embedded system 15 receives sensor information from either one of the sensors 7 and 8 that are connected to the brake unit 5 (depending on exercise mode). The control unit 17 steers the resistance on the basis of signals from one of the sensors that indirectly measure the performance of the person using the apparatus with respect to how much force is applied. In
Pulse sensor 7 measures the momentary position of the seat 19 (connected to the lineary moving wire rope 3) to be converted to information of the speed of the wire rope 3 and force sensor 8 measures the braking force of the brake unit 5.
A programmable constant current driver 13 in the embedded system 15 controls the brake unit 5 in a way steered by the control device 17 in a way that depends on which operation mode (which exercise mode) is chosen and in accordance with individual exercise parameters including a constant or varying set point for either the force (resistance of the brake) or position of the seat (speed of wire rope).
Depending on mode, (the mode possibilities including the isometric mode, the isotonic mode, the isokinetic mode or even the variokinetic mode or the cardiovascular mode) either the force to be applied on the brake or the speed of the seat is kept constant. In the isotonic, isokinetic and variokinetic modes, a set point for one of them is determined in accordance with the training parameters of a training program for a given person performing the training. In some individual training programs, the force and/or the speed set point might be allowed to vary within given ranges or in an unlimited way. In the isometric mode, the brake resists the movement of the moving means as controlled by the control unit with a counterforce of higher value with the force applied on the wire rope on the basis of the signal of a sensor 8 measuring the force applied and on the basis of the signal of a sensor 7 measuring the position of the seat 19 to be kept stationary.
The control mechanism for the different operation modes are described in connection with
The apparatus can also have an external biosignal measurement sensor 16 measuring body functions, e.g. the heart rate, the breathing etc. the signals of which is fed into the computer 18. These measurements can be taken into consideration when choosing the parameters for individual training programs during a particular exercise or to be used in a subsequent exercise.
Optionally, performance data and biometrical data can be collected during the exercise and be fed to the computer 18 to be used in the preparation and an updating of an individual training program. In a possible embodiment, biometric data could even be taken into consideration during training to adjust the set points.
Performance data, biometrical data and/or data of exercise results and analysis data might be shown on the user interface on the screen of the computer before, after or during the exercise.
The embedded system 15 is connected via the control unit 17 to the computer 18 having a user interface seen on the screen of the computer 18. The exercise results can be fed to the computer 18 after the training. Optionally, data of the performance of the training can also be fed to the computer 18 during an exercise session and be taken into consideration during the exercise or in the next exercise.
When the exercise apparatus works in the isometric mode, the user applied force does not result in any movement of the seat, and the knee angle of the user (the person performing the exercise) is kept constant in a desired angle, which can be called a kind of set point.
Here the goal is to keep the force applied constant in a value as selected by an isometric training program for the actual person performing the exercise. The static position of the seat is controlled by the signal from the pulse sensor 7 that measures the speed of the seat, which is zero in this example.
In this operation state therefore, the constant current driver 13 is used for controlling the speed set point on the basis of feedback signals form the pulse sensor 7. This means that the speed of the seat is kept constant (the movement back and forth) and the brake resistance is continuously adjusted to keep a certain value for the speed determined in accordance with a isokinetic training program for the person performing the exercise.
The brake resistance is controlled based on instructions from the control unit, which instructions are created on the basis of force information from the force sensor 8.
Information from the pulse sensor 7 is used to keep the speed set point. A digital controller 14 controls the speed set point adjusted on the basis of the sensor information.
In this operational state the constant current driver 13 is used for controlling the force set point on the basis of feedback signals form the force sensor 8 and instructions from the control unit created on the basis of position information from the pulse sensor 7. A digital controller 14 controls the force set point. The goal is to keep the force applied by the person contant and the resistance of the brake is adjusted to keep this force constant.
Claims
1. A system for controlling an exercise in an apparatus for training and measuring muscle strength, comprising:
- the apparatus with moving means actuated by force applied by a user,
- a magnetorheological brake unit resisting the movement of the moving means moved by user force applied,
- one or more sensors measuring the behavior of the moving means, and
- a processing unit connected to the control unit for selecting parameters of an exercise,
- a control unit actively controlling the resistance of the magnetorheological brake unit during the exercise on the basis of a sensor signal from one or more sensors, the signal being used depending on parameters selected,
- a first plate connected to the moving means, and
- a rotating shaft with a turning wheel supporting and being in moving engagement with the moving means, wherein
- the magnetorheological brake unit being connected via the rotating shaft to the turning wheel resisting the movement of the moving means via the turning wheel.
2. The system of claim 1, wherein the moving means comprises an inclined linearly moving wire rope extending around two turning wheels on a distance from each other.
3. The system of claim 1 wherein the function of the magnetorheological brake is based on an electromagnetic core consisting of rotating plates and coils and on the properties of a magnetorheological fluid.
4. The system of claim 1 wherein the magnetorheological brake unit resisting the movement of the moving means in only one direction.
5. The system of claim 3 wherein the magnetorheological brake resisting the movement of the moving means in the direction directed outwards of the rotating plates of the magnetorheological brake unit.
6. The system of claim 1 wherein the magnetorheological brake unit resists the movement of the moving means in accordance with a set value.
7. The system of claim 1 wherein the magnetorheological brake unit resisting the movement of the moving means caused by the user force applied in accordance with a set value for the resistance as a parameter for the exercise, the set value being determined on the basis of a desired speed of the moving means.
8. The system of claim 1 wherein the magnetorheological brake unit resisting the movement of the moving means caused by the user force applied in accordance with a set value for the resistance as a parameter for the exercise, the set value being determined on the basis of a desired force applied on the moving means.
9. The system of claim 1 wherein the processing unit having a user interface and a program for determination of the set value of the magnetorheological brake unit as a constant or varying parameter of an exercise.
10. The system of claim 1 further comprising an embedded system consisting of a feedback control loop for actively controlling the resistance by feedback control.
11. The system of claim 10, wherein the embedded system comprises said control unit receiving information from sensors, which are connected to the magnetorheological brake unit,
- a programmable constant current driver, which controls the brake unit, and
- a digital controller that controls the set point adjusted on the basis of the sensor signal.
12. The system of claim 10 wherein the feedback control loop is an integrated Proportional-Integral-Derivative, PID, controller.
13. The system of claim 1 further comprising a fuzzy logic controller for actively controlling the resistance by feedback control.
14. The system of claim 13 wherein the program determining additional parameters for the exercise, such as the mode and time of the exercise.
15. The system of claim 13 as applied for isometric training as the training mode,
- whereby the magnetorheological brake unit resists the movement of the moving means as controlled by the control unit with a counterforce of a higher value on the basis of the signal of a sensor measuring the force applied on the magnetorheological brake unit so that the as a consequence of the movement of moving means, the first plate remains on a pre-set position as measured by a sensor during an exercise of muscular work.
16. The system of claim 13 as applied for isokinetic training as the training mode,
- whereby the magnetorheological brake unit resists the movement of the moving means in accordance by a speed value set and controlled by the control unit and on the basis of a signal from a pulse sensor measuring the position of the first plate moving as a consequence of the movement of the moving means, and of a sensor measuring the force applied on the magnetorheological brake unit.
17. The system of claim 13 applied for isotonic training as the training mode,
- whereby the magnetorheological brake unit resists the movement of the moving means in accordance with a force value set and as controlled by the control unit and on the basis of the signal of a sensor measuring the position of the first plate moving as a consequence of the movement of the moving means and of a sensor measuring the force applied on the magnetorheological brake unit.
18. The system of claim 13 as applied for variokinetic training as the training mode,
- whereby the resistance of the brake is controlled in relation to the power produced by the user or in relation to the speed of the movement of the moving means.
19. The system of claim 1 further comprising a sensor measuring bio signals, the measured body performance to be used as a base for the parameters in an exercise.
20. The system of claim 1 wherein the apparatus being a leg press comprising a seat as the first plate, and a second plate as a footplate that can be manually pressed by a human being sitting positioned on the seat.
21. Apparatus for training and measuring muscle strength, comprising:
- moving means actuated by force applied by a user,
- a magnetorheological brake unit resisting the movement of the moving means moved by user force applied,
- a control unit actively controlling the resistance of the magnetorheological brake unit during the exercise on the basis of a sensor signal from one or more sensors, the signal being used depending on parameters selected,
- one or more sensors measuring the behavior of the moving means, and
- means to enable use of the apparatus in accordance with selected parameters of the exercise,
- wherein the apparatus further comprises
- a first plate being connected to the linearly moving means,
- a rotating shaft with a turning wheel supported by and being in moving engagement with the moving means,
- the magnetorheological brake unit resisting the movement of the moving means via the turning wheel.
22. The apparatus of claim 21, wherein the moving means comprises an inclined linearly moving wire rope extending around two turning wheels on a distance from each other.
23. The apparatus of claim 21 wherein the function of the magnetorheological brake is based on an electromagnetic core consisting of rotating plates and coils and on the properties of a magnetorheological fluid.
24. The apparatus of claim 21 wherein the magnetorheological brake unit resisting the movement of the moving means in only one direction.
25. The system of claim 23 wherein the magnetorheological brake resisting the movement of the moving means in the direction directed outwards of the rotating plates of the magnetorheological brake unit.
26. The apparatus of claim 21 further comprising a processing unit connected to the control unit for selecting parameters of an exercise.
27. The apparatus of claim 21 wherein the magnetorheological brake unit resists the movement of the moving means in accordance with a set value.
28. The apparatus of claim 27, wherein the magnetorheological brake unit resisting the movement of the moving means caused by the user force applied in accordance with a set value for the resistance as a parameter for the exercise, the set value being determined on the basis of a desired speed of the moving means.
29. The apparatus of claim 27, wherein the magnetorheological brake unit resisting the movement of the moving means caused by the user force applied in accordance with a set value for the resistance as a parameter for the exercise, the set value being determined on the basis of a the set value being determined on the basis of a desired force applied on the moving means.
30. The apparatus of claim 21 wherein the resistance of the magnetorheological brake unit is actively controlled by an embedded system with a feedback control loop for keeping the set point as selected in accordance with exercise mode and individual user goals.
31. The apparatus of claim 30, wherein the embedded system comprises said control unit receiving information from sensors, which are connected to the magnetorheological brake unit,
- a programmable constant current driver, which controls the magnetorheological brake unit, and
- a digital controller that controls the set point adjusted on the basis of the sensor signal.
32. The apparatus of claim 30 wherein the feedback control loop is an integrated Proportional-Integral-Derivative, PID, controller.
33. The apparatus of claim 31 further comprising a fuzzy logic controller for actively controlling the resistance by feedback control.
34. The apparatus of claim 21 being a leg press comprising a seat on the first plate,
- and a second plate as a footplate that can be manually pressed by a human being sitting positioned on the seat.
35. A method for controlling an exercise in an apparatus comprising moving means actuated by force applied by a user and a magnetorheological brake unit resisting the user force applied, the method comprising the steps of
- a) feeding user data and parameters of the exercise into a program run by a processing unit connected to the apparatus for controlling the parameters of an exercise to be performed,
- b) measuring the force applied by a user on the moving means during the exercise by means of one or more sensors measuring the behavior of the moving means, and
- c) controlling the resistance of the magnetorheological brake unit during the exercise on the basis of one or more sensor signals from said sensors and using the signal depending on parameters selected.
36. The method of claim 35, further comprising the steps of
- d) collecting and storing data of the exercise during performance in the form of exercise results, and
- e) analyzing the exercise results to be used as a basis of future exercises.
37. The method of claim 35 further comprising modifying exercise parameters on the basis of the analyzed exercise results or performance or biosignals during the exercise and repeating the exercise with modified parameters.
Type: Application
Filed: Sep 10, 2015
Publication Date: Dec 31, 2015
Inventor: Kari T. Ojanen (Kuopio)
Application Number: 14/850,401
