MATLAB Examples

Static and Kinetic Friction Library

This example shows a library containing blocks that allow you to actuate a single joint primitive at a time with these types of friction:

  • A mix of static and kinetic contact friction, proportional to static and kinetic friction coefficients and the force normal to the contact surface
  • Kinetic damping friction proportional to joint primitive velocity, either translational or rotational, but with opposite sign

These example library blocks are masked subsystems containing Simscape™ Multibody™ First Generation and Simulink® blocks.

The mixed static-kinetic friction block makes use of the Joint Stiction Actuator block from the Simscape™ Multibody First Generation Sensors & Actuators Library. If the connected joint primitive locks, that degree of freedom (DoF) is removed from the system. Simscape Multibody First Generation tests for locking and unlocking conditions with algebraic loops (non-time-based simulation steps) that can decrease the accuracy of your simulation, particularly if you use a fixed-step solver. Use such Joint Stiction Actuator blocks only if you need to lock and unlock jonits.

The kinetic damping friction block is a force element that applies a continuous friction force or torque via joint actuation using joint motion measured by a joint sensor.

Copyright 2008 MathWorks, Inc.