Examples

The SDK source has a set of ready-to-run scripts under python/examples/. Get the scripts working first, then model your own program on them. Run the commands below from the SDK source directory: with the collection environment that is third_party/taccap-gripper in the data-collection repository; with a standalone install it is TacCap-Gripper.

Every script selects a gripper with left, right or a full serial number, which can be omitted when only one gripper is attached. When a leader and a follower gripper are attached on the same side, use the full serial number. A script interrupts any other program using a gripper when it starts, so do not run example scripts while collection or control is running.

Scripts at a glance

Script	Purpose	Moves the motor or rewrites the gripper?
calibrate.py	Leader gripper travel calibration	Rewrites the gripper
leader_normalized_position.py	Read the leader gripper's opening	Read-only
fisheye_cal.py	View / write fisheye intrinsics	show is read-only, the rest rewrite the gripper
read_intrinsics.py	Export the wrist camera intrinsics	Read-only
wrist_camera.py	Wrist camera viewer	Read-only
ota_update.py	Gripper firmware upgrade	Flashes firmware
motor_ota_update.py	Motor firmware upgrade	Flashes firmware

Every script accepts --help to list its arguments. The follower gripper's scripts (self-check, keyboard control, impedance and force-position control and so on) are in Follower gripper → Example scripts.

Follower gripper

See Follower gripper → Example scripts.

Leader gripper

python python/examples/calibrate.py right
python python/examples/leader_normalized_position.py right

The calibration procedure is in Calibration and self-check.

Wrist camera

python python/examples/wrist_camera.py --list                  # list cameras and their serial numbers
python python/examples/wrist_camera.py <camera serial> --undistort   # undistorted image

Firmware

For a follower gripper see Firmware and motor upgrades; for a leader gripper see Firmware OTA upgrade.

Migrating from older versions

Programs written against 0.1.x / 0.2.x are mainly affected by these changes when upgrading to 0.4.x:

• The follower gripper now uses controllers: ImpedanceController or ForcePositionController, configured with for_spec(). The old ControlLoop, set_position() and similar interfaces have been removed.
• Positive velocity and torque now consistently mean the closing direction.
• Follower gripper firmware must be 1.2.5 or later; below 1.2.11 you are prompted to upgrade.
• The example scripts now select a gripper with a positional argument left / right / serial number, and the old control-type example scripts have been removed.
• The wrist camera frames delivered by gripper objects are now RGB by default.

When upgrading from 0.3.x to 0.4.x:

• Force-position control now uses a single torque-limited control law, which holds more steadily when grasping; snapshot().holding becomes true about 150ms later than before, so revalidate any program that relies on it.
• When closing to 0, the final state may be either HOLDING_FORCE or HOLDING_POSITION; both are normal.
• During operation, set_target(opening, grip_force) with a grip force above 1.1N·m now raises an error instead of being silently accepted.
• New g.motor.motor_version() reads the motor firmware version (from gripper firmware 1.2.14 on, this works regardless of the motor's communication mode).

Upgrading from 0.4.1 to 0.4.3 (no API changes):

• ForcePositionController no longer stutters when following a streamed target, at the cost of about 10–15ms more tracking lag.
• A stall short of a target that is still moving enters HOLDING_FORCE about 150ms later than before; review programs that rely on it to detect a grasp.
• The bundled follower firmware moves to 1.2.16; upgrade the firmware.

The full list of changes is in the SDK's CHANGELOG.