Abstract: A test system and a method includes applying a test drive signal to a physical test rig having a compliant actuator assembly for imparting loads to a test specimen. An actual response signal of the physical test rig and the test specimen to the test drive signal is obtained and an error as a function of the actual response signal and a selected response signal is calculated. If the error has not reached a selected threshold a new drive signal based on the error and a relaxation gain factor is obtained. The new drive signal is obtained and applied until the error reaches the selected threshold.

Abstract: A loading assembly used in a vehicle spindle test fixture includes a wheel adapter housing that is mountable to a vehicle spindle. A pair of vertical struts are provided. Each vertical strut is joined to the wheel adapter housing at spaced-apart first pivot connections. A bell crank is coupled to each end of the vertical struts at spaced-apart second pivot connections. An actuator is pivotally coupled to the bell crank at a third pivot connection. The location of the second pivot connections relative to the third pivot connection approximates the location of the first pivot connections relative to the spindle axis.

Abstract: A loading assembly used in a vehicle spindle text fixture to apply a lateral force parallel to a spindle axis of a vehicle spindle includes a support frame and a wheel adapter housing mountable to the vehicle spindle. A pair of vertical struts are pivotally joined to the wheel adapter housing. A first actuator is operably coupled to the vertical struts to apply a force along a vertical axis substantially perpendicular to the spindle axis and substantially perpendicular to a longitudinal axis of the vehicle. A pair of lateral struts are provided. Each lateral strut is pivotally joined to one of the vertical struts. A second actuator is operably coupled to the lateral struts to apply a lateral force.

Abstract: A wheelpan for use with tire coupled road simulators has a constrained layer damping material disposed between a top plate and a base plate, tuned mass dampers operably coupled to radially extending ribs or asymmetrical arrangement of the radially extending ribs in order to reduce vibrations of the wheelpan and noise generated therefrom.

Abstract: A loading assembly for a vehicle spindle test fixture includes a belt crank that pivots on a first axis to differentially displace two vertical struts which are attached to a wheel adapter housing in order to apply a braking moment to the vehicle spindle. A lever pivotally supported about a second axis is pivotally joined to the bell crank and is used to displace the bell crank, the vertical struts and the wheel adapter housing to apply a vertical force. A control link controls rotation of the bell crank about the first axis and is pivotally joined to the bell crank about a third axis. A second lever is pivotally supported for movement about the second axis and is pivotally joined to an end of the control link about a fourth axis. When a trailing arm suspension is to be tested, the bell crank, the first lever, the control link and the second lever are arranged to form a non-parallelogram linkage in order to induce a brake axis rotation when a vertical displacement is applied.

Abstract: A loading assembly used to apply selected forces and moments to a vehicle spindle includes a wheel adapter housing mounted to the vehicle spindle. In a first embodiment, the loading assembly reduces crosstalk between application of lateral forces and unintended braking moments, and lateral forces and unintended longitudinal forces. In a second embodiment, a second loading assembly is adjustable so that braking moments are induced when a vertical force is applied when the loading assembly is used on trailing arm suspensions.

Abstract: A mechanical tire emulator for spindle coupled road simulators. It simulates the real case tire impedance characteristics, including wheel hop, between the servo actuator produced vertical road input motion and the vehicle spindle. By simulating the loading impedance of the tire using a fluid pressure actuator loading through a compressible fluid cushion and substituting this actuator device for the rigid vertical link on prior art spindle coupled road simulators, the overall mounting arrangement is simplified over that when a tire itself is mounted on a wheel for such testing.

Abstract: A restraint and guidance system for testing vehicles has members on opposite sides of the vehicle which are secured to the vehicle, and a linkage member that permits the vehicle to move freely in the vertical, roll and pitch directions but which restrains movement in logitudinal direction of the vehicle. This permits the vehicle to move vertically freely, and to be rolled and pitched as guided by linkages that are completely decoupled from each other. The restraint system can be connected to actuators for controlling lateral loads. The kinematic paths of the linkage for reacting the loads are the same as if the vehicle body was inertially restrained, that is, acutaly moving in space during testing.

Abstract: A testing machine reproduces road excited vibrations for the purposes of testing vehicle wheel support specimens, for example McPherson strut assemblies used in front wheel drive vehicles, the system permits force inputs of horizontal, steering, vertical, and wheel hop loads, as well as, optionally, simulating braking loads. The loading fixture is compact, and substantially eliminates cross coupling of horizontal loading due to steering motion of the device, even though the steering motions provide for large steering excursions. The loading is tire coupled to simulate actual conditions, including wheel hop that occurs during road travel, and further provides for inherent cross coupling compensation to permit easy instrumentation and very close simulation of road induced vehicle vibrations during the testing process. The entire steering linkage can be tested, including tie rods, tie rod ends, and the wheel suspension mechanism.

Abstract: A restraint system for a vehicle undergoing tests with individual wheel supports and actuators. One of the supports has a wheel restraint to prevent lateral and fore and aft movement of the wheel. A diagonal wheel support has a wheel restraint to prevent lateral movement only.

Abstract: An improved rotary actuator assembly includes a stationary shroud extending between first and second spaced apart stationary support members that aids assembly of the rotary actuator and collects drain lubricating oil during operation. A rotating member is supported between the first and second stationary supports by bearings positioned within the first support and a bushing within the second support. The shroud covers a portion of the rotating member between the first and second stationary supports.