Reaching mobile robots

A robot comprising:

• an inverted pendulum body having first and second end portions;
• a counter-balance body coupled to the inverted pendulum body and configured to move relative to the inverted pendulum body;
• a manipulator arm having proximal and distal ends, the proximal end connected to the inverted pendulum body, the manipulator arm configured to move relative to the inverted pendulum body;
• at least one leg having first and second ends, the first end of the at least one leg prismatically coupled to the second end portion of the inverted pendulum body, the at least one leg having a variable length between the first and second ends;
• a drive wheel rotatably coupled to the second end of the at least one leg;
• and
• a controller in communication with the counter-balance body, the at least one leg, and the drive wheel, the controller configured to perform operations comprising:
• driving the robot across a surface to approach a reach point;
• extending the manipulator arm forward of the reach point;
• and
• maintaining the drive wheel and a center of mass of the robot rearward of the reach point by moving the counter-balance body relative to the inverted pendulum body while extending the manipulator arm forward of the reach point.