Abstract: A method for adaptive estimation of a road surface adhesion coefficient for a vehicle with complex excitation conditions taken into consideration comprises the following steps: 1) designing an estimator according to a single-wheel dynamics model of a vehicle, and estimating a longitudinal tire force and a road surface peak adhesion coefficient under longitudinal excitation; 2) designing an estimator according to a two-degree-of-freedom kinematic model of the vehicle, and estimating a tire aligning moment and a road surface peak adhesion coefficient under excitation of a lateral force; and 3) determining an excitation condition met by the vehicle according to a vehicle state parameter, performing fuzzy inference to obtain limits achievable by current longitudinal and lateral tire forces, and designing a fusion observer to fuse estimation results. The method achieves favorable robustness, improves real-time capability, and can be performed quickly and accurately.

Abstract: Techniques and methods for testing a structural integrity of a vehicle. For instance, the vehicle may use suspension(s) to lift corners of the vehicle, where lifting the corners creates a torsion force in the body of the vehicle. The vehicle may then use sensor(s) to determine a deflection that is caused by the torsion force. Next, the vehicle may determine a stiffness associated with the body of the vehicle using the force that was applied to lift the corners and the deflection. After determining the stiffness, the vehicle may compare the stiffness to a baseline stiffness in order to determine whether there is a problem with the structural integrity of the vehicle. The baseline stiffness may include s standard stiffness or be based on a previous test of the vehicle. If the vehicle determines that there is no problem, then the vehicle may continue to operate as intended.

Abstract: Provided is a test apparatus for an actuator, which can easily switch whether to establish or undo the coupling between an actuator to be tested and a load part configured to apply load to the actuator. A test apparatus for an actuator includes a load part for outputting load to be applied to an actuator to be tested, first levers for swinging around a rotational shaft in connection with an output from the load part, an idler link coupled to the output from the actuator to be tested, a second lever coupled to the idler link in a swingable manner and for swinging around a rotational shaft that is arranged coaxially with the rotational shaft of the first levers, and a clutch mechanism for coupling together the first levers and the second lever and undoing the coupling.

Abstract: Techniques are described for estimating surface friction coefficients using lateral force excitations of one or more rear wheels of a rear wheel steering vehicle. In one example, a computing system is configured to cause excitation of a rear wheel using a lateral force that causes the rear wheel to initiate turning. The computing system may determine one or more slip angles that result from the excitation and determine a relationship between the lateral force and the slip angles. From the lateral force and slip angle relationship, the computing system may estimate the friction coefficient of a surface and may cause maneuvering of the rear wheel steering vehicle, or of another networked vehicle, to be based at least in part on the friction coefficient estimated for a particular driving surface.

Abstract: The disclosure discloses a wheel testing machine. The wheel testing machine comprises a wheel clamping part and a test detection part, the device can meet the requirements of wheel test detection in use.

Abstract: An automotive vehicle includes an actuator configured to control vehicle steering, a sensor configured to detect a yaw rate of the vehicle, and a controller. The controller is configured to estimate a yaw rate and lateral velocity of the vehicle via a vehicle dynamics model based on a measured longitudinal velocity of the vehicle, calculated road wheel angles of the vehicle, and estimated tire slip angles of the vehicle. The controller is configured to receive a measured yaw rate from the sensor, and to calculate a difference between the measured yaw rate and the estimated yaw rate. The controller is configured to apply a model correction to the vehicle dynamics model using a PID controller based on the difference, and to estimate a vehicle position based on the estimated lateral velocity and the measured longitudinal velocity. The controller is configured to automatically control the actuator based on the vehicle position.

Abstract: A rail vehicle includes a truck having wheels for engaging a railroad track, a bolster supported by the truck, and a tank supported by the bolster for storing a lading. A measurement system measures the level of the lading within the tank and includes gauges and a controller. The gauges are disposed at selected points on the bolster for sensing at least one of lateral and longitudinal localized displacement experienced by the bolster during motion of the rail vehicle. The controller calculates the level of the lading within the tank and compensates for changes in the level of the lading during motion of the rail vehicle in response to signals generated by the gauges.

Abstract: A system includes sensor modules, each associated with a wheel on a vehicle, and a receiver unit. Each sensor module calculates a rotation period associated with the wheel during turn mode vehicular motion and determines rotation direction of the associated wheel during straight vehicular motion. A data packet that includes a unique identifier for the sensor module, the rotation period, and the rotation direction are transmitted from each sensor module for receipt at the receiver unit. The receiver unit determines the steered wheels and non-steered wheels based on the rotation period, and the receiver unit can determine which wheels are on the right side or the left side of the vehicle based on the rotation direction. Knowledge of the steered and non-steered wheels and the rotation direction of the wheels, enables the receiver unit to assign locations of the sensor modules, and hence positions of the wheels of the vehicle.

Abstract: In a method of inspecting a wheel hub unit configured by attaching a rolling bearing, which has an inner ring and an outer ring, to a hub wheel, an acoustic inspection dement is arranged so as to be in contact with an outer peripheral face of the outer ring, and the wheel hub unit (components except the outer ring) is rotated to measure an acoustic value of the outer ring and hence conduct inspection. When the wheel hub unit (components except the outer ring) is rotated, a preloading load that is equal to or higher than a load at which an axial internal clearance of the rolling bearing is a negative clearance is applied to the rolling bearing, and the axial internal clearance of the rolling bearing A is changed from a positive clearance before application of the load to a negative clearance after application of the load.

Abstract: A torque sensor for a human-powered object includes a spindle connecting crank arms of the object. In one embodiment, the object can be a bicycle. The torque sensor further includes at least one strain gauge mounted to the spindle in a shear pattern to measure shear strain perpendicular to a radius of the spindle. In some embodiments, the torque sensor further includes a carrier fixed to a hollow interior of the spindle, where at least one strain gauge is mounted to the spindle via the carrier. Advantageously, the torque sensor provides a low cost method to measure power.

Abstract: A method of assessing a condition of a wheel on a vehicle involves contactlessly determining distance of a first location on the wheel from a fixed point not on the wheel at a first time while the vehicle is moving and contactlessly determining distance of a second location on the wheel from the fixed point at a second time after the vehicle has moved. The two distances are compared to determine an offset between the first and second locations on the wheel. The offset provides an indication of tire wearing angle of the wheel while the vehicle is moving. The method can be used to assess wheel alignment and wheel suspension. An apparatus and system for effecting the method involves the use of a displacement sensor, especially an optical displacement sensor (e.g. a laser) for making the distance determinations. The system and apparatus is completely contactless and only one stationary displacement sensor is required to make the appropriate distance measurements to the wheel on a moving vehicle.

Abstract: A test bench for motor vehicles and/or axles of motor vehicles for simulating gyroscopic torques of a rotating wheel includes a wheel replacement system connected to an axle of the motor vehicle. The wheel replacement system includes a wheel replacement mass and a driver for driving the wheel replacement mass. The test bench also includes an arrangement for applying testing forces, testing torques and testing movements in a longitudinal, lateral and/or vertical direction to the motor vehicle and/or axles of the motor vehicle. The driver is configured to set the wheel replacement mass in rotation. The arrangement for applying testing forces, testing torques and testing movements is configured to generate a gyroscopic torque of the wheel replacement mass which is set in rotation, by applying testing forces, testing torques and testing movements in the longitudinal, lateral and/or vertical direction to the motor vehicle and/or the axles of the motor vehicle.

Abstract: To be able to simulate any desired kind of driving state with a test vehicle it is envisioned to connect an active secondary vehicle 2 to the front or rear of the test vehicle 1, and wherein the secondary vehicle 2 is equipped with its own drive and load device 3 by which the test vehicle 1 is braked and/or pushed additionally to its own deceleration and/or acceleration.

Abstract: A flaw detection testing device that carries out a flaw detection test on an outer peripheral surface of a clinched portion used to fix an inner ring member of a hub unit to a hub spindle includes: a flaw detection sensor; a clearance setting member that contacts the outer peripheral surface of the clinched portion to set a clearance between the flaw detection sensor and the outer peripheral surface of the clinched portion at a predetermined value; a fixing device that fixes a position of the flaw detection sensor with the clearance between the flaw detection sensor and the outer peripheral surface kept at the predetermined value; and an actuating device that moves the clearance setting member in such a direction that the clearance setting member is separated from the outer peripheral surface of the clinched portion with the position of the flaw detection sensor fixed by the fixing device.

Abstract: A checking device for checking automotive suspension system comprises a rod and a work piece fixed on the rod. The work piece includes a work surface for pressing against a tread portion of the wheel. Rotating the rod can make the wheel and the suspension system connected thereto sway in a direction different from the forward rotating direction of the wheel. Then the user can find out the faults by the abnormal sound made by the respective components of the suspension system, so that the checking device for checking automotive suspension system is capable of reducing the time for finding out the faults in the suspension system.

Abstract: A method for determining the absolute angular position of a steering wheel of an electric power-assisted steering column of a motor vehicle, including a means for measuring a dynamic parameter while the vehicle is running and including among others, the steps of periodically determining a multi-turn relative angular position, determining at least one dynamic parameter relating to the running conditions of the vehicle using the means for measuring said parameter, determining an absolute steering-wheel angle calculated according to at least one dynamic parameter, and weighting the calculated value of the absolute steering-wheel angle according to a test of the validity of the calculated value of the absolute steering-wheel angle and the origin of said value, in other words, the measurement means used to determine said at least one dynamic parameter.

Abstract: An apparatus for calculating a wheel speed is described herein which includes a tire force sensor, a time measurement unit, an angular velocity calculation unit and a wheel speed calculation unit. The tire force sensor outputs a signal in accordance with an amount of modification of a bearing. The time measurement unit measures a time interval between peak values of the signal output from the tire force sensor. The angular velocity calculation unit calculates an angular velocity by dividing an angle between balls positioned within the bearing by the time interval measured by the time measurement unit. The wheel speed calculation unit calculates the wheel speed by multiplying a distance from a center of the bearing to a center of the ball by the angular velocity calculated by the angular velocity calculation unit.

Abstract: To simplify the development of a hybrid vehicle the invention envisions simulating the hybrid vehicle by using a test vehicle 1 comprising a first axle 5 that is powered by a combustion engine and a second passive, non-powered axle 6, and wherein the axle that is present in the real hybrid vehicle and powered by an electric motor is simulated on the test vehicle 1 by an active secondary vehicle 2 that is hooked up to the test vehicle 1 and that is equipped with its own drive 3 and additionally to the combustion engine brakes and/or pushes the test vehicle 1, and wherein the secondary vehicle 2 is connected with a control device 7 of the test vehicle 1.

Abstract: A wheel support bearing assembly with sensor and in-wheel motor integration, that can sense with improved accuracy the forces acting on a contact point between a wheel and a road for precise control of an electric motor unit and/or a vehicle. The bearing assembly includes a bearing unit that rotatably supports a hub of a drive wheel, an electric motor unit, and a reduction gear unit between the electric motor unit and the bearing unit. A sensor unit is associated with an outer ring of the bearing unit. The sensor unit includes a strain generator and at least one measuring sensor attached to the strain generator. The strain generator includes a thin plate including at least two fixation contact segments fixed in contact with an outer diameter surface of the outer ring.

Abstract: The following features may be carried out: providing a wheel suspension alignment system having four measuring heads situated in a known position with respect to one another; recording a wheel or a measuring target mounted on it in an initial position of the vehicle; shifting the vehicle from the initial position to at least one further position; recording a wheel, or a measuring target mounted on it, of the vehicle standing in the further position; recording a reference target in at least one of the initial position and the further position of the vehicle, and determining from this an absolute scale; carrying out local 3D reconstructions for determining the translation vectors, the rotation vectors and the wheel rotational angles as well as the wheel rotational centers and the wheel rotational axes of the wheels; and determining the wheel suspension alignment parameters of the vehicle.

Abstract: A sensor mounting arrangement of a wheel assembly having a spindle defining an elongated cavity is provided. The spindle rotatably supports a wheel. The sensor mounting arrangement comprises a tube, a wire harness, and a sensor assembly. The tube is configured to be partially received in the elongated cavity of the spindle. The wire harness is routed through the tube. The sensor assembly is connected to a leading end of the wire harness wherein the leading end is configured to be disposed proximal to the wheel.

Abstract: A sensor equipped wheel support bearing assembly, in which detection error is relieved to accurately estimate load is provided. A vehicle body fitting flange of an outer member of the bearing assembly has a front elevational shape of line symmetry or of point symmetry. A sensor unit including a strain generating member having two or more contact fixing segments to be fixed to the outer member and a strain sensor is provided at an arcuately sectioned portion lying from the flange to the outer member, or an outer peripheral surface portion of the outer member adjoining to the outboard side thereof, or a position crossing a line segment passing through a center of a rolling element or a position adjoining thereto. Alternatively, a plurality of sensor units are provided on the outer periphery of the outer member in a fashion spaced circumferentially equidistantly.

Abstract: The invention relates to a test method for bogies (12) and a test stand suitable for carrying out the method, said test stand being additionally suitable for disassembling and assembling components of corresponding bogies (12). According to the proposed solution, the loads incurred by a bogie during its intended use are simulated in a known manner on a test stand designed for this purpose on the still unfinished bogie (12). To this end, forces are directed into the bogie (12) such as those caused by the weight of a car body and by other operation-related load conditions. The effect of these load conditions on the bogie (12) and/or of a track on which the bogie (12) runs is described by measured values, which are obtained by means of measuring sensors and are computer-processed.

Abstract: Embodiments of the present invention provide a method, system and apparatus for tracking a rotatable object. A device for tracking a rotatable object comprises a body, the body comprising a tracking portion. A device for tracking a rotatable object further comprises an attachment section connected to the body, for attaching the device to the rotatable object. The body and the attachment section are configured for balanced rotation when the rotatable object rotates.

Abstract: There is proposed a test wheel arrangement (1) for testing a motor vehicle while the tyres are stationary, which test wheel arrangement (1) has a shaft section (5) which can be attached to a wheel hub (7) of a motor vehicle and on which a test wheel (3) is mounted to be freely rotatable.

Abstract: A sensor device adapted to be associated with a vehicle wheel includes a package enclosing at least one sensor and an electronic data processing apparatus and at least one antenna arranged on the package for at least one among the wireless transmission of data generated by the electronic apparatus and the wireless reception of data to be provided to the electronic apparatus. The at least one antenna is shaped to adhere to surfaces of the package.

Abstract: An apparatus testing axle shafts includes i) a test bench to receive a tubular axle shaft including a wall exhibiting variable known external and internal radius profiles, ii) at least one ultrasonic probe to analyze at least one selected portion of the wall in a selected angular sector and thus acquire analysis data, iii) a controller to control the test bench to place each probe on the wall external or internal surface in at least one first site selected as a function of its profiles and a possible loading of the shaft such that it analyses the first and second selected wall portions respectively in at least one first and at least one second selected angular sector oriented in first and second opposing longitudinal or transverse directions, to thus acquire analysis data for various relative angular positions of the shaft in relation to the probe, and iv) a processor to create from these acquired analysis data maps representing the transverse or longitudinal orientations and positions of indications of echoe

Abstract: An improved speed sensing system is disclosed for a machine, such as a truck, that has an axle with an end and an axis. The machine further includes a sensor non-rotatably coupled to the end of the axle and coaxial with the axis. A wheel hub is rotatably coupled to the axle and a wheel cover is coupled to the wheel hub. The machine further includes a magnet coaxially disposed with the axis and coupled to the wheel cover for rotation about the axis as the wheel rotates. The sensor generates signals based on the rotational speed of the magnet and the wheel. For non-rotating axles that are solid or include solid spindles, a passageway for a communication line between the sensor and electronic control module (ECM) may be easily drilled thereby making the disclosed system easy to add to an existing machine or vehicle.

Abstract: A sensor equipped wheel support bearing assembly, in which detection error is relieved to accurately estimate load is provided. A vehicle body fitting flange of an outer member of the bearing assembly has a front elevational shape of line symmetry or of point symmetry. A sensor unit including a strain generating member having two or more contact fixing segments to be fixed to the outer member and a strain sensor is provided at an arcuately sectioned portion lying from the flange to the outer member, or an outer peripheral surface portion of the outer member adjoining to the outboard side thereof, or a position crossing a line segment passing through a center of a rolling element or a position adjoining thereto. Alternatively, a plurality of sensor units are provided on the outer periphery of the outer member in a fashion spaced circumferentially equidistantly.

Abstract: A flaw detection testing device that carries out a flaw detection test on an outer peripheral surface of a clinched portion used to fix an inner ring member of a hub unit to a hub spindle includes: a flaw detection sensor; a clearance setting member that contacts the outer peripheral surface of the clinched portion to set a clearance between the flaw detection sensor and the outer peripheral surface of the clinched portion at a predetermined value; a fixing device that fixes a position of the flaw detection sensor with the clearance between the flaw detection sensor and the outer peripheral surface kept at the predetermined value; and an actuating device that moves the clearance setting member in such a direction that the clearance setting member is separated from the outer peripheral surface of the clinched portion with the position of the flaw detection sensor fixed by the fixing device.

Abstract: A sensor-equipped bearing for a wheel rotatably supporting the wheel relative to a vehicle body includes an outer member (1) provided with a double-row raceway surface (3) on an inner periphery thereof, an inner member (2) provided with raceway surfaces (4) opposing to the raceway surfaces (3) of the outer member (1), one of the outer and inner members serving as a stationary member, double-row rolling elements (5) interposed between the outer and inner raceway surfaces, a sensor fitting member (22) fixed to a peripheral surface of the stationary member, and a plurality of strain sensors (23) attached to the sensor fitting member (22) for measuring a strain thereof.

Abstract: A device and method for simulating rotation of a wheel on a vehicle having a rotatable wheel rotation sensor. A motor is coupled to a rotatable portion of the rotation sensor, and is operated to rotate the rotatable portion of the rotation sensor according to a pulse train simulating a wheel skid.

Abstract: The invention relates to a test method for bogies (12) and a test stand suitable for carrying out the method, said test stand being additionally suitable for disassembling and assembling components of corresponding bogies (12). According to the proposed solution, the loads incurred by a bogie during its intended use are simulated in a known manner on a test stand designed for this purpose on the still unfinished bogie (12). To this end, forces are directed into the bogie (12) such as those caused by the weight of a car body and by other operation-related load conditions. The effect of these load conditions on the bogie (12) and/or of a track on which the bogie (12) runs is described by measured values, which are obtained by means of measuring sensors and are computer-processed.

Abstract: To simplify the development of a hybrid vehicle the invention envisions simulating the hybrid vehicle by using a test vehicle 1 comprising a first axle 5 that is powered by a combustion engine and a second passive, non-powered axle 6, and wherein the axle that is present in the real hybrid vehicle and powered by an electric motor is simulated on the test vehicle 1 by an active secondary vehicle 2 that is hooked up to the test vehicle 1 and that is equipped with its own drive 3 and additionally to the combustion engine brakes and/or pushes the test vehicle 1, and wherein the secondary vehicle 2 is connected with a control device 7 of the test vehicle 1.

Abstract: A wheel and sensor assembly includes a U-shaped bracket assembly mounting to and moving with a wheel assembly. One or more sensor device(s) such as camber angle and slip angle sensors mount to the bracket assembly for operatively measuring one or more wheel assembly parameter(s) during vehicle use. The bracket assembly mounts to the wheel assembly and turns therewith. The bracket assembly positions the sensor device(s) in operative optimal proximity to the road surface during vehicle use under actual operating conditions.

Abstract: In a method for wheel suspension alignment, the following steps are carried out: providing a wheel suspension alignment system having four measuring heads situated in a known position with respect to one another, of which each has a monocular picture recording device, the relative position of the measuring heads with respect to one another being known; recording in each case one wheel or a measuring target mounted on it in an initial position of the vehicle, using each of the four measuring heads; shifting the vehicle from the initial position to at least one further position; recording in each case one wheel, or a measuring target mounted on it, of the vehicle standing in the further position, using each of the four measuring heads; recording a reference target having a known pattern mounted on the vehicle, using one of the four measuring heads in at least one of the initial position and the further position of the vehicle, and determining from this an absolute scale for the measuring heads; carrying out loc

Abstract: A method of checking the operating characteristics of an electronic unit (1) fitted on a wheel (2) of a vehicle (3) and adapted to transmit, to a central processing unit (7), data frames representative of operating parameters of the wheel according to a procedure for transmitting streams (A) of frames (a) consisting in ordering n successive transmissions of each data frame. This checking method consists in analyzing, on the transmission of each stream of data frames, the number m of data frames actually acquired by the central processing unit (7), so as to deduce from the successive analyses a reception ratio Tr representative of the ratios ?m/?n, and in ordering the transmission, by the central processing unit (7), of a preventive indication when the reception ratio Tr becomes less than a predetermined reception threshold.

Abstract: Device 1 for detecting the angular position of a shaft of an electric motor relative to a nonrotating element, comprising a reduction gear 5 comprising an input connected in rotation to the shaft 2, and an output such that the output of the reduction gear 5 moves over an angle of less than 2?, a single-revolution angular position sensor 26 being placed to measure the angle of the output of the reduction gear 5 and an angular position sensor 27 being placed on the input of the reduction gear 5.

Abstract: In a wheel support bearing assembly including a plurality of rolling elements (5) interposed between an outer member (1) and an inner member (2), a sensor unit (21) is fitted to one of the outer member and the inner member, which serves as a stationary member. The sensor unit includes a sensor mounting member (22) and a strain sensor (23) fitted to the sensor mounting member. The sensor mounting member has a plurality of contact fixing portions (22a, 22b) that are fixed to at least two locations spaced a distant from each other in a direction circumferentially of the outer member. A cutout (24) is provided in the outer member at respective positions corresponding to the neighboring contact fixing portions of the sensor mounting member, so as to extend in an axial direction. The strain sensor is arranged intermediate between the neighboring contact fixing portions.

Abstract: An apparatus testing axle shafts including i) at least one ultrasonic probe to analyze, in a selected angular sector, selected portions of a wall exhibiting known variable internal and external radius profiles of a tubular axle shaft and thus acquire analysis data, ii) a controller to determine, as a function of the profiles and possible loading and environment of the shaft, at least one first and at least one second selected site on the external or internal surface of the wall where each probe is to be placed manually, to analyze at least one first and at least one second selected portion of the wall respectively in at least one first and at least one second selected angular sector oriented in first and second opposing longitudinal or transverse directions, and thus acquiring analysis data for various relative angular positions of the shaft in relation to the probe, and iii) a processor to create from these acquired analysis data maps representing the transverse or longitudinal orientations and the positions

Abstract: An apparatus testing axle shafts includes i) a test bench to receive a tubular axle shaft including a wall exhibiting variable known external and internal radius profiles, ii) at least one ultrasonic probe to analyze at least one selected portion of the wall in a selected angular sector and thus acquire analysis data, iii) a controller to control the test bench to place each probe on the wall external or internal surface in at least one first site selected as a function of its profiles and a possible loading of the shaft such that it analyses the first and second selected wall portions respectively in at least one first and at least one second selected angular sector oriented in first and second opposing longitudinal or transverse directions, to thus acquire analysis data for various relative angular positions of the shaft in relation to the probe, and iv) a processor to create from these acquired analysis data maps representing the transverse or longitudinal orientations and positions of indications of echoe

Abstract: A wheel is provided for a test vehicle. The wheel has a rim and a hub, and whereby at least one force sensor is placed in the flux of force between the hub and the rim. A test stand is provided with the test vehicle that has multiple vehicle wheels and one or more of these vehicle wheels is embodied as a wheel with a force sensor placed between the hub and the rim. An appropriate procedure is provided for determining the aerodynamic characteristics of the test vehicle. Especially with a test stand equipped with a wide belt, the forces relevant to measurement of the drag coefficients can be reliably measured with the aid of the specific wheel with the force sensor. Use of overhead scales that have an undesired effect on the flow can be dispensed with.

Abstract: The invention relates to a bearing arrangement for mounting at least one machine element on a support, wherein the machine element is movably mounted on the support, wherein the bearing arrangement is provided with at least one measuring sleeve and with at least one measuring element on the measuring sleeve, wherein the measuring sleeve is formed separately from the support and wherein the measuring element is provided at least for measuring physical parameters and processes in the bearing arrangement.

Abstract: A wheel and brake assembly (10) having a torque bar (24) supported at a mid-span location. The torque bar (24) can be pre-loaded at a mid-span location. The pre-load can be effected by a spacer block (150) that is interposed between the wheel well and the torque bar (24). The method and device of the present invention can be used with existing wheel and brake assemblies. The spacer block can be a two-part spacer block.

Abstract: A method and apparatus for evaluating NVH characteristics of a mechanical system including a torque-transmitting assembly having drive and driven members drivingly engaging each other. The torque-transmitting assembly is characterized by transmission error between the drive and driven members. The method comprises the steps of measuring a parameter representing NVH characteristics of the mechanical system during operation thereof upon a predetermined test cycle so as to obtain at least one NVH characteristic corresponding to at least two discrete values of the transmission error. The apparatus comprises a supporting member mounted to a casing for rotatably supporting the drive member and being axially movable relative to the casing so as to selectively adjust the transmission error, and an actuator assembly operatively associated with the supporting member for selectively adjusting position of the supporting member relative to the casing in order to selectively control the transmission error.