Short-Transient Discrete Time-Variant Filter Dedicated for Correction of the Dynamic Response of Force/Torque Sensors

Abstract

The perception of touch opens new perspectives for so-called ’intelligent robotics’. Force/torque sensors are currently a key component of autonomous assembly processes or of the dynamically developing sector of collaborative robots. Response time is a critical parameter of force control, which has a direct effect on impact forces when the robot initiates contact with the environment. This paper indicates parameters of one of commercial force/torque sensors by JR3, in particular, its pre-defined low-pass filters. Their stationary nature introduces i.e. significant delay in the time domain, resulting in a negative impact on the overall dynamics of force control. To remedy the problem, our proposed approach is to employ a novel discrete time-variant filter with appropriately modulated parameters, owing to which it is possible to suppress the amplitude of the transient response and, at the same time, to increase the pulsation of damped oscillations; this results in the improvement of the dynamic properties in terms of reducing the duration of transients. Differences between a commercial, stationary filter and the recommended discrete time-variant filter have been shown experimentally, using a dedicated test environment.