# 362 Project Proposal

### Briefly, what are you making and what are you making it out of?

We are making a claw game with a pre-built robot arm.

For the robot arm, we get cartesian control commands from the user via joystick/keyboard, compute joint angles using inverse kinematics, convert joint angles to PWM signals, and finally send the PWM values to the corresponding servos.

In the robot arm's workspace, there will be a variety of objects laid out. The player maximizes their score by picking as many objects as possible and dropping them through a hole in the bottom of the workspace. The workspace is reset by powering off the arm according to the steps below, adding the objects back, then turning on the system again. there will be enough objects in the workspace to last atleast a few games.

In the hole, there is an PIR sensor that records each dropped object that is attached to an interrupt that adds 1 to the player's score. There would be music playing (Eye of the Tiger - Rocky, No time for Caution - Interstellar) playing to encourage the player, accomplished through using the MIDI Interpreter from HW7. An SPI-controlled LCD display will display the time remaining and the user's score.

The robot arm consists of 6 hobby servos: each one uses 5V of power, accepts a 3.3V PWM data signal, has a 180 degree turn range, and has a average max speed of 0.13sec / 60 degrees with no load. The maximum reach radius from the center of the arm is 0.36m. Servos 1-5 control the arm's position/orientation, and Servo 6 controls the roll/pitch movement of the end-effector. Joystick motions provide the ADC input for Servos 1-3, and potentiometers provide the ADC inputs for Servos 4-6.

To prevent joint-limit violations, we will hard-code limits directly on the PWM outputs with explicit tests. We'll also define low velocity limits for each joint by setting a minimum step size between consecutive duty cycles. We will incorporate an Emergency STOP for manual power shutoff to the arm, placed outside the robot's range of motion. For further protection, we will enclose the robot arm in a cage.

The following is the safety protocol that must be followed when operating the robot:
Startup:
1. Ensure that the robot arm is inside the cage
2. Ensure that the e-stop is pressed down (powered off state)
3. Ensure that no hands or human is inside the cage
4. Connect power to the system
5. Turn on robot system by turning the e-stop to activate the arm

During:
1. At no point when the e-stop is turned on should any bodily parts be present within the cage.

Power off/Emergency Situation:
1. Shutdown the robot by pressing the e-stop button
2. Handle the robot arm
3. If the robot arm is unused, unplug the power cable

To further secure the arm from being operated by unauthorized individuals, the e-stop will be an electrical keylock.

### Briefly, how will you demonstrate it?

We will allow the user to control the robot arm to play the timed claw game and score points with the rules specified in the previous question

### Briefly, how will we define the criteria for a successful project? (If your demonstration does not meet these criteria, your score will be negatively affected.)

With our system, a human should be able to score at least 5 points within the time limit.

There should be no jerky motion with the arm/end-effector motion.

The music should be smooth without interruption and play the two songs that we listed (No time for caution and Eye of the Tiger).

The LCD screen should clearly display the user's score and time remaining.