Wheel action force detector for detecting axle forces absent brake torque

Abstract

A device for measuring action force of a wheel includes a vehicle axle upon which the wheel is mounted, the vehicle axle having a stress neutral line, and a stress detecting sensor having at least one strain gauge. The stress detecting sensor is disposed within the vehicle axle so as to detect at least one of a horizontal shear stress and a vertical sheer stress with the at least one strain gauge being one of aligned with or proximate the stress neutral line thereby permitting substantial removal of axle torque influence from an output of the stress detecting sensor. A signal processing circuit processes the output of the stress detecting sensor.

Description

[0001] 1. Technical Field[0002] The present invention relates to a device for measuring action force of a wheel for detecting road surface frictional force, vertical drag, road surface friction coefficient, etc. which can be a constituent element of a brake system with skid control for preventing lock (seizure) of the wheels of a vehicle on sudden stops or a traction control system for preventing excessive slip of the wheels at acceleration, and a device for measuring stress of a structure for measuring stresses produced in optional structures.[0003] 2. Prior Art[0004] The antilock brake system (ABS) of the conventional vehicle such as an automobile generally employs the principle of controlling the brake action automatically according to the chassis speed and wheel speed in such a manner that the slip ratio will fall with a certain range [cf. Japanese Patent Publication No. 59-30585 and Japanese Kokai Patent Publication No. 60-61354). The relationship between road surface friction ...

AI Technical Summary

Benefits of technology

This solution enables precise measurement of road surface frictional forces and coefficients, reducing braking distances and improving ABS and traction control system performance by directly measuring dynamic wheel interactions with the road, regardless of surface conditions.

Problems solved by technology

Therefore, in the above-mentioned system, the braking force may not be maximal depending on road surface condition and the minimum braking distance cannot be obtained in such cases.

Furthermore, since the chassis speed is estimated from the wheel speed, control of the slip ratio is deficient in precision.

However, in this system, the tire torque is indirectly determined by arithmetic operation from the wheel angular acceleration and bake fluid pressure but because of indefinite constants such as the wheel inertia efficiency and the braking efficiency of the brake, the precision of calculated values is not sufficiently high.

In this case, too, there is the same problem as in the ABS wherein control is based on the wheel speed.

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