Abstract: The present invention includes a central control system and method for fine tuning a cigarette manufacturing process. A measurement device captures measurements of particular cigarette properties. The measurement data is sent to and stored in a central database. Once sufficient measurement data has been stored, the data is loaded into an optimization program that outputs optimized controlled parameters that may be used by individual control systems to better control the properties of the cigarettes during manufacture. The central control system and method may be used with both off-line and in-line measurement devices, and can communicate and control such devices regardless of the manufacturer thereof.

Abstract: The subject of the invention is a process for adjusting a processing unit, whereby at least one set value is varied from a starting value to a final value. In this case, the target value of a correcting value is set based on the starting value and the final value of the adjustment value, and the value of the correcting value is run up from its starting value to its target value using a parameter-dependent transfer function. A control variable is measured, the value of the control variable is compared to a comparison value, and in the case of deviations of the value of the control variable from the comparison value, at least one parameter of the transfer function is corrected.

Abstract: An apparatus for controlling a two degree of freedom process comprises a first controller, a second controller, and a process model. The three components are oriented in such a way that the first controller receives input from a first variable and the second controller receives input from a second variable. The process model is a model of the process process and provides feedback to the first controller. Furthermore, the orientation of the controllers isolates the first controller from the second variable and isolates the second controller from the first variable when the process model matches the process. Since each controller shapes a response to only one variable, the transfer functions of each controller can be chosen to meet stringent performance standards.

Abstract: A two-wire field-mounted process device with multiple isolated channels includes a channel that can be an input channel or an output channel. The given input or output channel can couple to multiple sensors or actuators, respectively. The process device is wholly powered by the two-wire process control loop. The process device includes a controller adapted to measure one or more characteristics of sensors coupled to an input channel and to control actuators coupled to an output channel. The controller can be further adapted to execute a user generated control algorithm relating process input information with process output commands. The process device also includes a loop communicator that is adapted to communicate over the two-wire loop.

Abstract: A flexible closed-loop controller capable of being quickly and easily configured for a broad range of applications. The controller contains a set of control elements that may be configured or reconfigured for any specific application. Built-in configuration management automates configuration of the control elements dependent on user commands or operating conditions. The controller is autonomous after initial configuration, although it may be used interactively. This flexible closed-loop controller is suitable for switching power supplies, linear amplifiers, AC inverters, battery chargers, electronic loads, temperature and pressure management, motor or actuator drives, as well as industrial automation, data acquisition, and automatic test equipment. The controller reduces development time and cost, reduces parts count and cost, and improves performance and reliability of real-time closed-loop systems.

Abstract: An object of the invention is to provide an anomaly diagnosis apparatus of a machine installation for eliminating the need for the user to have a dedicated analytical instrument or a skill required for anomaly diagnosis of a sliding member and enabling the user to easily make an anomaly diagnosis request with a small burden and get the diagnosis result promptly.

Abstract: A method for controlling a solenoid using a single coil solenoid for both course and fine adjustment. A resistor or series of resistors may be used in parallel/for current controlled solenoids or in series for voltage controlled solenoids for allowing course or finite control of the solenoids.

Abstract: A Robust Model-Free Adaptive controller is disclosed for effectively controlling simple to complex systems including industrial processes, equipment, facilities, devices, engines, robots, vehicles, and appliances. Without the need of re-designing a controller or re-tuning the controller parameters, the inventive controller is able to provide a wide robust range and keep the system under automatic control during normal and extreme operating conditions when there are significant disturbances or changes in system dynamics. Because of its simplicity and capability, the control system is useful for building flexible and adaptive production systems to fulfill the on demand manufacturing needs of the new e-commerce environment.

Abstract: A device for calculating the steady state behavior of a controller includes an amount generating unit for generating the amount of deviation of the regulator, a first threshold value calculation unit that detects whether the amount of deviation of the regulator has fallen below a first threshold value and then starts a lag time delay unit, and a second threshold value calculation unit that detects whether the amount of deviation of the regulator has fallen below a second threshold value. A signal transmission unit transmits a ready message signal when the lag time delay unit has reached a predetermined lag time and the second threshold value calculation unit has detected that the amount of deviation of the regulator has fallen below the second threshold value.

Abstract: With highly heterogeneous groups or streams of minerals, physical segregation using online quality measurements is an economically important first stage of the mineral beneficiation process. Segregation enables high quality fractions of the stream to bypass processing, such as cleaning operations, thereby reducing the associated costs and avoiding the yield losses inherent in any downstream separation process. The present invention includes various methods for reliably segregating a mineral stream into at least one fraction meeting desired quality specifications while at the same time maximizing yield of that fraction.

Abstract: The present invention includes a system and method for fine tuning the process of controlling the weight of a flow of material, such as a rod of material in a production facility. A control actuator in communication with a PID controller and PID control loop is used to change the unit volume of the flow so as to maintain a target unit weight. A measurement device captures unit weight measurements of the flow at intervals over the length of the flow. A change is introduced to a control actuator while the PID controller and PID control loop are disabled, and appropriate weight measurements of the flow are continually captured along with the control actuator's “feed back” position; a process that may be repeated several times. Once sufficient weight measurement data has been captured, the data is loaded into an optimization program that outputs optimized controlled parameters that may be used by the PID controller and control loop to better control the weight of the flow of material.

Abstract: A state based adaptive feedback/feedforward PID controller includes a model set component, communicatively coupled to a process input, having a state variable defining a number of process regions, and a number of models grouped into the process regions. Each of the grouped models includes a plurality of parameters having a value selected from a set of predetermined initial values assigned to the respective parameter. The adaptive controller further includes an error generator communicatively coupled to the model set component and a process output. The error generator configured to generate a model error signal representative of the difference between a model output signal and a process output signal. The error generator, communicatively coupled to a model evaluation component, is configured to compute a model squared error corresponding to a model and correlating the model squared error to parameter values represented in the model.

Abstract: An acceleration limiting electronic filter for a position motion control system is disclosed. The filter is used in conjunction with a position control system to precisely control the position of a device. The present invention limits the acceleration content of a position command signal to some value less than what the control system can execute so that the control system does not clip the acceleration and degrade control.

Abstract: A tuned run-to-run controlled system is disclosed that provides tuned run-to-run control of a system. The system includes a controlled system coupled to a tuned run-to-run controller, which contains a feedback controller coupled to a tuner. Tuned run-to-run controller determines a feedback command based on a nominal gain, a maximum gain, a process error, and a tuning gain.

Abstract: A control system for a plant is disclosed. According to this system, a value of a switching function which is defined as a linear function of a deviation between the output of the plant and a control target value, is calculated. A reaching mode input is calculated. The reaching mode input contributes to placing a deviation state quantity which is defined based on the deviation, onto a switching straight line on which the value of the switching function becomes zero. The reaching mode input is corrected according to the value of the switching function. A control input to the plant is calculated with a response specifying type control, and the control input includes the reaching mode input. The plant is controlled with the calculated control input.

Abstract: A robust Artificial Neural Network controller is proposed for the motion control of a magnetic disk drive voice coil motor (voice coil motor). The neural controller is used to approximate the nonlinear functions (actuator electromechanical dynamics) of the voice coil motor while having on line training. One main advantage of this approach, when compared with standard adaptive control, is that complex dynamical analysis is not needed. Using this design, not only strong robustness with respect to uncertain dynamics and non-linearities can be obtained, but also the output tracking error between the plant output and the desired reference can asymptotically converge to zero. Additionally, standard offline training, utilizing training vectors to stimulate the voice coil motor, is not required.

Abstract: Automatic speed loop gain adjustment of a feedback control system begins by setting up a phase margin range and a gain margin range. A speed open loop condition is provided by separating a speed command value from a speed feedback value. White noise is input into the feedback control system where the speed open loop condition has been made. A phase margin and a gain margin are then detected and comparisons are made with the phase margin range and the gain margin range, respectively. The speed loop gain is adjusted if the comparison results for either one of the detected phase margin and the detected gain margin fall outside of the associated phase margin range or gain margin range. Once the adjustment of the speed loop gain is complete, the position loop gain of the position control loop is adjusted on the basis of the adjusted speed loop gain.

Abstract: A disk apparatus includes a DSP (digital signal processor), and a DSP core of the DSP receives a feedback input from a pick-up, and generates a focus control pulse and a tracking control pulse. That is, a focus servo loop and a tracking servo loop are formed. The DSP core detects a phase difference between a sine wave of a target frequency and a sine wave superposed on an input signal, and adjusts a gain of the servo loop so as to bring a DC component of a correlation signal correlated with the phase difference to a 0 level. More specifically, if the DC component of the correlation signal exceeds a predetermined threshold value, an adjusting amount of the gain is rendered large, and greatly brought closer to the 0 level. On the other hand, if the DC component of the correlation signal is equal to or less than the predetermined threshold value, the adjusting amount of the gain is rendered small, and gradually brought to the 0 level.

Abstract: Method of analyzing and optimizing a multistage manufacturing process which includes a number of standard steps that are carried out identically and which are followed by tuning steps that are carried out in order to achieve predefined product properties, their type, number and exit being variable. The individual steps relate to at least one production-specific property an are recorded quantitatively in an electronic database. The property can be, for example, a proportion of the quantities, a proportion of the costs, or the effects of an individual step on a product property to be achieved. Examples of a multistage manufacturing process are the manufacture of a coating from a plurality of individual components and additives. With the aid of the information compiled in a database, individual steps can be reduced in terms of their number and their extent.

Abstract: An adaptive motion controller for driving a servo motor. The adaptive motion controller includes a computer control module which stores information for configuring an amplifier to a specific servo motor. The amplifier has a chip which will configure the amplifier for a specific servo motor upon receiving the stored information. A computer control module receives the stored information and delivers it to the chip.

Abstract: A hybrid stabilization system for isolating a pointing vector of a gimbal from the motion of a vehicle base is provided. The hybrid stabilization control system includes a rate feedback loop generating a rate feedback compensation value in response to a measured rate difference between a pointing vector rate of motion and a vehicle base rate of motion, a rate feedforward loop generating a rate feedforward compensation value in response to a measured inertial vehicle base rate of motion, a position feedback loop generating a position feedback compensation value in response to a measured position difference between a pointing vector angular position and a vehicle base angular position, a position feedforward loop generating a position feedforward compensation value in response to a measured inertial vehicle base angular position.

Abstract: In tuning a controller for a process in a feedback control system, a method is provided for bringing the system into asymmetric self-excited oscillations for measuring the frequency of the oscillations, average over the period value of the process output signal and average over the period control signal and tuning the controller in dependence of the measurements obtained. An element having a non-linear characteristic is introduced into the system in series with the process and set point signal is applied to excite asymmetric self-excited oscillations in the system. An algorithm and formulas are given for identification of the process model having the form of first order plus dead time transfer function. PI controller settings are given as a function of the dead time/time constant ratio. An apparatus for performing the method is disclosed.

Abstract: A method for determining the measure of control provided to a process by a control system. The determines process model parameters for a simple and complex model of the process and uses those parameters along with the value of the process variable and the final control element position to predict the off control data. The method also uses the process model parameters to determine the optimal tuning and then forecasts the optimal process performance from the predicted off control data and the determined optimal tuning.

Abstract: A control system must establish the same throttle position repeatedly to obtain fuel efficiency and prevent speed dropping during idling. Sensors determine the throttle position or other engine parameter associated with the throttle position and create an analog signal. The information is processed by a analog-to-digital converter which places the signal into a discrete level. A controller receives this signal and compares it to a point assigned between two discrete levels representing the desired throttle position or engine parameter. Therefore, the signal will never equal the assigned point. The controller makes corrections based on this comparison after every iteration because the error will never reach zero.

Abstract: A method for modeling and design of a coupled cavity laser device is provided. A coupled cavity laser device includes a resonant cavity that includes at least two sub-cavities. The method of the invention includes selecting device characteristics of the laser, performing round trip iteration calculations, including an inter-cavity field exchange, for each sub-cavity, testing to determine whether a convergence has been reached, and computing a device output beam characteristic.

Abstract: A two-wire field-mounted process device with multiple isolated channels includes a channel that can be an input channel or an output channel. The given input or output channel can couple to multiple sensors or actuators, respectively. The process device is wholly powered by the two-wire process control loop. The process device includes a controller adapted to measure one or more characteristics of sensors coupled to an input channel and to control actuators coupled to an output channel. The controller can be further adapted to execute a user generated control algorithm relating process input information with process output commands. The process device also includes a loop communicator that is adapted to communicate over the two-wire loop.

Abstract: The present invention includes a system and method for fine tuning the process of controlling the weight of a flow of material, such as a rod of material in a production facility. A control actuator in communication with a PID controller and PID control loop is used to change the unit volume of the flow so as to maintain a target unit weight. A measurement device captures unit weight measurements of the flow at intervals over the length of the flow. A change is introduced to a control actuator while the PID controller and PID control loop are disabled, and appropriate weight measurements of the flow are continually captured along with the control actuator's “feed back” position; a process that may be repeated several times. Once sufficient weight measurement data has been captured, the data is loaded into an optimization program that outputs optimized controlled parameters that may be used by the PID controller and control loop to better control the weight of the flow of material.

Abstract: A method for providing independent static and dynamic models in a prediction, control and optimization environment utilizes an independent static model (20) and an independent dynamic model (22). The static model (20) is a rigorous predictive model that is trained over a wide range of data, whereas the dynamic model (22) is trained over a narrow range of data. The gain K of the static model (20) is utilized to scale the gain k of the dynamic model (22). The forced dynamic portion of the model (22) referred to as the bl variables are scaled by the ratio of the gains K and k. The bi have a direct effect on the gain of a dynamic model (22). This is facilitated by a coefficient modification block (40). Thereafter, the difference between the new value input to the static model (20) and the prior steady-state value is utilized as an input to the dynamic model (22). The predicted dynamic output is then summed with the previous steady-state value to provide a predicted value Y.

Abstract: A system and method for controlling a device such that device operates in a smooth manner. The system may switch between control architectures or vary gain coefficients used in a control loop to control the device. As the architecture or gains are switched, the control signal may be smoothed so that the device does not experience an abrupt change in the control signal it receives. In one embodiment, the control signal may be smoothed by adding a decaying offset value to the control signal to create a smoothed control signal that is applied to the device.

Abstract: An industrial process material flow within an industrial process is controlled by a process control loop that includes a process controller, a field device controller and a field device in the process as well as process variable feedback from the process to the process controller. Both the process controller and the field device controller, such as a valve controller, are fine-tuned so that their interaction is taken into account and controller parameters, which provide an optimal control loop performance are found. This results in a significant improvement in the control loop performance, i.e., in a lower process variability, as compared with the traditional tuning method, which does not take into account the interaction between the two controllers.

Abstract: Disclosed herein is a calibration method for a two-stage actuator control system. The calibration method includes the steps of inserting a sinusoidal disturbance dv(k) into a control input uv(k) to a main actuator, comparing uv(k) and uv(k)+dv(k) to obtain an open-loop gain, and setting the reciprocal of the open-loop gain in a gain compensator for the main actuator. The calibration method further includes the steps of adding a sinusoidal disturbance dp(k) to an input to a subactuator, and comparing the sinusoidal disturbance dp(k) with an output y(k) from the two-stage actuator to obtain a disturbance input-displacement gain. A design nominal value is divided by the disturbance input-displacement gain to obtain a compensation gain, which is then set in a gain compensator for the subactuator.

Abstract: A method and apparatus for controlling a non-linear mill. A linear controller is provided having a linear gain k that is operable to receive inputs representing measured variables of the plant and predict on an output of the linear controller predicted control values for manipulatible variables that control the plant. A non-linear model of the plant is provided for storing a representation of the plant over a trained region of the operating input space and having a steady-state gain K associated therewith. The gain k of the linear model is adjusted with the gain K of the non-linear model in accordance with a predetermined relationship as the measured variables change the operating region of the input space at which the linear controller is predicting the values for the manipulatible variables.

Abstract: A network receiver is configured for receiving a base band carrier signal from another network transceiver via a network medium. A variable gain amplifier generates an amplified base band signal. An A/D converter generates a sequence of sample values representing the base band signal in response to the amplified base band signal. A gain control circuit monitors the sequence of sample values for a plurality of monitoring intervals in a sample time period, determines a range for each monitoring interval, and determines a gain setting for the variable gain amplifier.

Abstract: A method and system are invented for adaptively and automatically retuning a closed-loop servo motor that is operating within normal limits. A first active set of configurable tuning constants is assigned to the servo motor, and motor performance is periodically measured to determine if performance is outside a retuning threshold, in which case the active set of configurable tuning constants is replaced by selecting a replacement set of tuning constants from a finite group of discrete predesigned sets of tuning constants. Actual performance of the servo motor is remeasured, and this process is repeated if the performance remains outside the retuning threshold. The predesigned sets of tuning constants are derived and stored in the servo motor software, typically as a result of pretesting the servo motor model by the manufacturer, for example using manual retuning.

Abstract: The invention is a method for positioning a conveying mechanism having a holding portion for semiconductor wafers. Respective provisional position coordinates of an orienting teaching standard position and a container teaching standard positions are inputted into a controlling unit in advance. A wafer to be conveyed precisely positioned with respect to and held by the holding portion is conveyed and placed on the rotating orienting device according a control based on the provisional coordinates of the orienting teaching standard position. A posture detector then detects the eccentric volume and eccentric direction of the wafer. Appropriate position coordinates are made by amending the provisional coordinates. Then, a wafer to be conveyed precisely positioned with respect to the container teaching standard position is conveyed and placed on the rotating orienting device according a control based on the provisional coordinates of the orienting teaching standard position.

Abstract: A simulation procedure simulates the response of a process control loop having a controller tuned according to a set of tuning parameters to illustrate, for example, the overshoot, oscillation, response time, etc. of the controller as tuned. As part of the simulation procedure, a robustness map, such as a plot illustrating phase margin versus gain margin or other robustness qualities, is created and the robustness of the simulated control loop may be plotted as a point on the robustness map. During the creation of the robustness map, different sets of tuning parameters for a region in which the process control loop is stable are determined and stored and the corresponding robustness qualities of the loop having a controller tuned according to these tuning parameters are also determined and stored. The robustness map is then displayed to a user showing the stable region.

Abstract: An open-loop and closed-loop control method is described for starting up or shutting down a process component of a technical process. At least one manipulated variable that is fed to the process is formed by a control device and an upstream model-assisted pilot control. The pilot control contains an optimizer and a process model. The optimizer is fed at least one command variable for the technical process. At least one optimized model manipulated variable which the optimizer outputs is fed to a process model of the pilot control and, is added to at least one output variable of the control device to form the manipulated variable. A model output variable of the process model is fed to the control device as a set-point and fed back to the optimizer along with variables which cannot be measured in the technical process. A device for implementing the method is also described.

Abstract: A numerical controlling device and a tooling apparatus having thereof, in which performance required for the machining is greatly improved correspondingly to a degree of importance according to a type of the machining and thus high efficiency and high accuracy in the machining can be obtained, by referring a database based on a type of a specified cutting tool and workpiece, and of a machining mode including an operating path of a movement of the cutting tool and workpiece, and by selecting a control parameter which relates to an adequate operating speed and operating position in the entire operating path during machining and non-machining.

Abstract: A method is described for the closed-loop control of a time-delayed process having compensation, in particular for temperature control. After a setpoint value step-change, the manipulated variable is set at a first constant value in an open-loop controlled operation, an IT1 model is identified on the basis of the step-change response and a PI controller is parametrized, which closed-loop controls the process into a second steady state. Subsequently, a more exact process model having compensation is determined and is used for the control adjustment.

Abstract: A method and apparatus for controlling a non-linear mill. A linear controller is provided having a linear gain k that is operable to receive inputs representing measured variables of the plant and predict on an output of the linear controller predicted control values for manipulatible variables that control the plant. A non-linear model of the plant is provided for storing a representation of the plant over a trained region of the operating input space and having a steady-state gain K associated therewith. The gain k of the linear model is adjusted with the gain K of the non-linear model in accordance with a predetermined relationship as the measured variables change the operating region of the input space at which the linear controller is predicting the values for the manipulatible variables. The predicted manipulatible variables are then output after the step of adjusting the gain k.

Abstract: A method for providing independent static and dynamic models in a prediction, control and optimization environment utilizes an independent static model (20) and an independent dynamic model (22). The static model (20) is a rigorous predictive model that is trained over a wide range of data, whereas the dynamic model (22) is trained over a narrow range of data. The gain K of the static model (20) is utilized to scale the gain k of the dynamic model (22). The forced dynamic portion of the model (22) referred to as the bi variables are scaled by the ratio of the gains K and k. The bi have a direct effect on the gain of a dynamic model (22). This is facilitated by a coefficient modification block (40). Thereafter, the difference between the new value input to the static model (20) and the prior steady-state value is utilized as an input to the dynamic model (22). The predicted dynamic output is then summed with the previous steady-state value to provide a predicted value Y.

Abstract: A closed-loop control of a servo motor in which multiple closed-loop terms of a motor command are adaptively tuned and selectively activated to achieve both stable operation and improved performance. The motor command includes a first term proportional to an error signal, a second term based on the integral of the error signal, and a third term based on the rate of change of the measured feedback signal, and representing the kinetic energy of the system. The first term is continuously active, whereas the second term is only activated when the rate of change of the measured feedback signal is below a threshold, and the third term is only activated when the error signal is within a reference window, thereby allowing relatively high gains while ensuring stable operation.

Abstract: An adaptive motion controller for driving a servo motor. The adaptive motion controller has an amplifier including a voltage command which can be set at a voltage at which the amplifier will be operated, a frequency selector which can be set at a frequency at which the amplifier will be operated, a power supply having a current feedback, and a control for driving the servo motor in a test mode wherein the voltage command is set at a selected voltage, and the frequency selector is sequentially set with a series of different frequencies. The servo motor is operated at each frequency, and the frequency of the series of frequencies that has the lowest current feedback is determined and the frequency selector is set at that frequency when the amplifier is operated to drive the servo motor.

Abstract: A disturbance estimated type control system and a gas compressor control system that are insensitive to a parameter variation such as a heat load variation and a rotating speed change and a method of designing a disturbance estimated type control system are provided. A disturbance is applied to a control object. An input signal and an output signal are inputted in an observer and a disturbance is estimated. A deviation between the output signal and a target value is calculated by a subtractor. This deviation is subject to compensations by a compensator and outputted as a control signal. This control signal is subtracted from a disturbance estimated value from the observer by a subtractor. Therefore, the disturbance estimated value among estimated values of the observer is fed back so as to cancel an actual disturbance.

Abstract: An auto-tuner for use in tuning a control element in a process control network having distributed control functions includes a first tuning element located in the field device in which the control element is operating and a second tuning element located in a different device that communicates with the first device via a communication network. The first tuning element controls the operation of the control element during the dynamic data capture phase of an auto-tuning procedure, collects data during this phase of the auto-tuning procedure and determines one or more process characteristics from the collected data. The first tuning element then communicates the determined process characteristics to the second tuning element via the communication network.

Abstract: A method for generating a valve drive signal using a variable gain PI controller in a mass flow controller. The method includes multiplying an error signal with a proportional gain factor to generate a proportional signal. The method also includes implementing an integral function on the error signal. The integral function includes an integral gain factor which functions as the variable gain in the PI controller. For set-point signals less than a normalized predetermined percentage of the maximum set-point, the gain factor is equal to [ ( 1 0.1 - 1 ) ⁢   ⁢ A + B ] , where A is a first gain constant and B is a second gain constant.

Abstract: A control system for an actuator employs a number of discrete feedback controllers each tuned to different operating conditions or parameters. The competing outputs of the feedback controllers are combined using fuzzy logic which dynamically effects a combination depending on the output values. One set of rules in the preferred embodiment gives greater weighting to the output having relatively lower effect on the control process.

Abstract: Process for setting controller parameters (PA, K1 . . . Kn) of a state controller (SC) which, together with a plant (PL), forms a closed control circuit (C). The controller parameters (PA, K1 . . . Kn) are variable only in such manner that, in a representation of the poles (P1 . . . P5) of the closed control circuit (C) in a complex frequency range plane (FP, IM, RE), the setting of the controller parameters causes a shift of the poles (P1 . . . P5) approximately along semi-circular arcs (K) and/or origin rays (A1 . . . A3). It is advantageous that according to the process of the invention the setting of the controller parameters (PA, K1 . . . Kn) of the state controller (SC) can be performed by setting predetermined setting parameters that are, from a control-technological standpoint, easily understandable and recognizable. Such parameters are, for example, amplitude factor (&kgr;), rise time (&mgr;), or transient recovery time (t).

Abstract: A method and circuit for controlling a controlled variable by a closed-loop control circuit comprising at least two controllers and a control device with a reference stage and a controlled system generating the controlled variable. The reference stage is supplied with a reference variable, which determines the set point of the controlled variable, the maximum value of which is predefined as a function of the control limits of the control device formed as the sum of the control limits of the controllers of the control device. A first controller of the control device is provided with a control deviation, which is formed as the difference between the reference variable and the actual value of the controlled variable. The other controllers of the control device are provided with a control deviation, which is formed, respectively, as the difference between the control deviation of the respective preceding controller and the actual value of the controlled variable of the additional controller.

Abstract: Methods and apparatus for efficient management of memory and force output in a force feedback system including a host computer and a force feedback device. A representation of device memory is maintained on the host computer to allow the host computer knowledge and control over storage and force effects in the device memory. A host cache for force effects is provided to allow almost unlimited numbers of force effects to be created for the device, where any force effects not able to fit in device memory are stored in the host cache. Other aspects of the invention include a playlist stored on the device of force effects being played by the device, and management of force output using relatively small, discrete time intervals.