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Topsy is a modular system designed for occasional measurements of all composite inertial, kinematic, and compliance parameters which appear in today's sophisticated mathematical simulation models. The emphasis in its design is not “production-line” testing, but research: the operator can observe the vehicle's reaction to developing forces; and as insights develop he can modify the test program as he goes along. Test errors are minimized by running all tests under servo control with continuous display of all data and recording of all known error sources, while the operators closely monitor the test and the developing data. The test facility is organized around an “infrastructure” consisting of baseplates, vehicle locating fixtures, scales, hydraulic and pneumatic power sources, interchangeable valve assemblies and actuators, and transducers. These are organized along with specialized devices into the several forms required for the different tests.

This paper describes an easily-installed, programmable, battery-powered, “series servo second steering wheel”. The steering machine is designed to execute any 16384-step steering program with force and velocity capabilities significantly greater than those of the human driver. Its EPROM memory contains sixteen separate programs, which can be programmed to duplicate any steering input with fidelity and repeatability. During the execution of a program, the handwheel is mechanically “grounded” to eliminate driver interference with measurement of steering angles and torques. The program also outputs auxiliary signals that can be used to control vehicle throttle and brakes, data recorders, or other devices. The paper describes the steering machine's design and operation, its measured capabilities, and some of the SAE, ISO, and rollover test protocols for which it is designed.