Robotics and Automation Laboratory

Simulation and optimal control of skid steer mobile manipulators

Caterpillar 262C skid-steer loader model and simulation files for the Spatial Vector Algebra toolbox by Roy Featherstone [Spatial]

Version 1: SSMM moving a flat surface in open loop.

The following files contain the model parameters and Matlab/Simulink scripts to simulate the Caterpillar Cat 262C skid-steer loader using Roy Featherstone's Spatial toolbox for Matlab.

Instructions concerning the SSMM model and simulation..

Model parameters file.

Simulation example parameters file.

Simulink simulation file.

Movie showing the agreement of simulated and measurements of traveled distance and turning rate..

Version 2: SSMM moving a mound with a controlled arm tracking a straight line.

This Matlab/Simulink simulation can be obtained either as zip file to be extracted into the directory where your installation of the Spatial toolbox is: ssmm_sim_v2.zip, or as zip file that includes version 2 of the Spatial toolbox: spatial_v2.zip. The latter can be extracted and copied to any location of your drive and only requires you to change directory to the location of the file '..<your path>/spatial_v2/ssmm_sim' and the run 'RunDemo' from Matlab's command line interface. In both cases, the REAME.txt file contained in the folder 'ssmm_sim' explains in detail the way to get the simulation running. The steps are similar to those of version 1 above. However, in this second version everything is provided in a single compressed file for the user's convenience.

Video 1

Version 3: SSMM with eight wheels (four on each side).

This Matlab/Simulink simulation can be obtained either as zip file to be extracted into the directory where your installation of the Spatial toolbox is: ssmm_sim_8_wheels.zip, or as zip file that includes version 2 of the Spatial toolbox: spatial_v3.zip. The latter can be extracted and copied to any location of your drive and only requires you to change directory to the location of the file '..<your path>/spatial_v2/ssmm_sim' and the run 'RunDemo' from Matlab's command line interface. In both cases, the REAME.txt file contained in the folder 'ssmm_sim' explains in detail the way to get the simulation running. The steps are similar to those of version 1 above. However, in this second version everything is provided in a single compressed file for the user's convenience.

Video 2

Forward dynamics equations for a skid-steer mobile manipulator with 1-DOF arm and wheel-ground interactions. The equation paramerters were chosen to representing the Caterpillar 262C skid-steer loader

The file with the equations can be obtained here: ssmm_20150807g0_eqs_cat262.pdf.

Caterpillar 262C skid-steer loader field tests to measure dynamic model parameters

The following data sets were acquired on a Caterpillar Cat 262C skid-steer loader equipped with a Crossbow RGA-300CA IMU and gyroscope sensor. The data files are saved in Matlab's .mat format. The data structure for the IMU measruemntes is explained below.

Data Set 1 - Straight Line without Load