Method of traversing difficult terrain

A method of remotely controlling a ground robot including main right and left driven tracks and rear right and left pivotable arms each including a driven track via an operator control unit configured to operate the right and left driven tracks, the pivotable arms, and the pivotable arm driven tracks, the method comprising:

• using the operator control unit to pivot the rear right and left pivotable arms to trail the main right and left driven tracks at a fixed angle relative to and above the ground;
• using the operator control unit to operate the main right and left driven tracks to traverse the ground;
• using the operator control unit to operate the driven tracks of the rear right and left pivotable arms;
• and
• using the operator control unit to traverse an obstacle and, as the forward end of the robot pitches upward, the rear driven tracks engaging the obstacle to advance the robot forward over the obstacle and to prevent the robot from tipping over backwards.

A method of remotely controlling a ground robot including main right and left driven tracks and rear right and left pivotable arms each including a driven track via an operator control unit configured to operate the right and left driven tracks, the pivotable arms, and the pivotable arm driven tracks, the method comprising:

• upon a mode command from the operator control unit, automatically pivoting the rear right and left pivotable arms to trail the main right and left driven tracks at a fixed angle relative to and above the ground;
• operating the main right and left driven tracks to traverse the ground;
• and
• operating the driven tracks of the rear right and left pivotable arms at the same speed as the main tracks.

A method of operating a mobile remotely controlled ground robot in difficult terrain, the method comprising:

• pivoting rear driven tracked arms of the robot rearward and upward at a fixed angle θ relative to main driven robot tracks having a length L;
• driving the main tracks of the robot forward to traverse the ground;
• traversing an obstacle having a height h by driving the main tracks to traverse an obstacle pivoting the forward end of the robot upwards;
• and
• at least one of the rear driven tracks then driven and engaging the ground and/or obstacle to advance the robot forward over the obstacle and to prevent the robot from tipping over backwards, wherein angle θ is approximately equal to arcsin(h/L).