Modeling of dynamic friction behaviors of hydraulic cylinders

Design and Evaluation of a Bowden-Cable-Based Remote Actuation System for Wearable Robotics

“…Hydraulic RAS offer high power density at both the actuation unit and the output, and thanks to quasi-incompressible media, high bandwidths can be achieved [15]. However, hydraulic cylinders are affected by nonlinear friction, which makes control difficult and decreases efficiency [16]. More importantly, hydraulic lines stiffen with increasing pressure, limiting the range of motion (ROM) of the user.…”

Experimental Study of Friction Characteristics of Pneumatic Cylinders

“…These behaviors do not agree with the behaviors reported by Tran et al 6) , though the reason for the different behaviors is not clear. The dynamic friction force caused by the rod packing is much smaller than the entire friction force and almost traces the steady-state friction characteristic as shown in Fig.12 (b), while the 8) . Therefore, the hysteresis exists in a low speed range for grease lubrication and in a wide speed range for oil lubrication.…”

Development of a New Hydraulic Ankle for HYDROïD Humanoid Robot

“…Previous studies shows that the effects of friction are most noticeable at the pistons for hydraulic applications [31]. This leads to the integration of friction in the virtual model with the aim of making it more realistic.…”

“…3, an experimental identification leads to a static friction force F s for the ankle first prototype equals to 52.5 [N]. Therefore, the values of µ f and c f are chosen accordingly to F s and based on the material combination of the parts of the first ankle mechanism [31]. These values were found to be: Several simulations with different friction parameters were carried out in order to study their sensitivity to the static force F s .…”