Assignment 2 information

• Get some graph paper for problems 1 and 2. You should note that all lines in these problems (for friction cone edges and contact normals) will pass through grid points. Remember that lines whose slopes are negative reciprocals of each other are perpendicular.

• Use friction cones for problem 1, do not use free body diagrams. Although you can easily solve part (a) with a free body diagram, the other parts are complicated. Using friction cones is by far the easiest method.

• I've put together some course notes on friction cones (postscript, pdf). I'll leave some hardcopies outside my office door.

• For problem 2, assume that the robot must have greater than zero clearance, i.e. if the robot is 3 units wide in some direction, and there is a space that is 3 units wide between two obstacles or an obstacle and a wall, then the robot cannot pass through that space.

  A more precise way of stating this is to assume that the C-space obstacles are closed (i.e. they include the boundary).

• For problem 1, the mass is not specified because it doesn't matter.