Demo Instructions

These instructions only support the Bazel build system (not CMake). For getting started with Bazel, see http://drake.mit.edu/bazel.html.

Running the demos

A variety of demos are available. In general, to run a demo, open a terminal and execute commands like the ones shown below. End the demo by closing any window, or Ctrl-C in the terminal. All of the launched programs will be closed.

$ cd drake
$ bazel run automotive:DEMO_NAME_HERE

The following demos are available:

• One SimpleCar under user control and one TrajectoryCar driving around in a figure eight on an open plane:

  bazel run automotive:demo -- --num_simple_car=1 \
      --driving_command_gui_names=0 --num_trajectory_car=1
  

  This will show one ado car driving in a fixed trajectory, and one ego car which can be driven anywhere on the infinite plane. (See "Driving the Prius" below to make it go.)

• A 3-lane dragway with four TrajectoryCar vehicles traveling down each lane at different speeds plus one SimpleCar and one MaliputRailcar:

  bazel run automotive:demo -- \
      --num_dragway_lanes=3 \
      --num_trajectory_car=12 \
      --num_maliput_railcar=1
  

Driving the Prius

Ensure that the (very small) pygame window has focus, then use your arrow keys to drive around. If you have a joystick / steering wheel, you can use that, too (see steering_command_driver.py for details).

Alternatively, you can generate throttle and steering commands using the command line, for example:

$ cd drake
$ bazel-bin/automotive/steering_command_driver --mode=one-time --throttle=1.0 --steering-angle=0.4

Running the dynamics

The following instructions describe how to run car_sim_lcm — a dynamics-based simulation of a sedan that approximates a Toyota Prius. The model is simplistic; it does not model engine, transmission, or suspension dynamics, but it is still useful in terms of illustrating Drake's dynamics-based simulation capability. The model consists of four wheels where the front wheels are steered using Ackermann steering and the rear wheels are fixed to an axle that spans the width of the vehicle (they rotate passively). In addition to being steerable, the front wheels also have velocity-controlled actuators that enable the vehicle to move forward and backward. PID controllers are used to control both the steering angle and front wheel rotational velocities. A simple sliding friction model is used for the contacts between the wheels and the ground. The input reference values for the PID controllers are settable via LCM using lcmt_driving_command_t messages published on channel "DRIVING_COMMAND". The current state of the simulation can be visualized in Drake Visualizer.

To run car_sim_lcm, open a new terminal and execute the following commands:

$ cd drake
$ bazel build automotive:demo automotive:car_sim_lcm
$ bazel-bin/tools/drake_visualizer &
$ bazel-bin/automotive/steering_command_driver &
$ bazel run automotive:car_sim_lcm

Then drive the car using the pygame window per "Driving the Prius" above.

You can also add a speed bump with a command-line switch:

$ bazel run automotive:car_sim_lcm -- --with_speed_bump

Enable Chase Cam Mode in the Drake Visualizer

To avoid the car moving out of view within the Drake Visualizer, we recommend setting Drake Visualizer to chase cam mode. To do this, select Menu, 'View`, and 'Camera Control Panel'. Within this control panel, click on 'Select Target', and then click on the Toyota Prius. In the control panel, change 'Track Mode' to be 'Smooth Follow' and increase the elevation to 30 degrees.