ECE 495 Project 3: Shocker Actuator Subsystem and Website Design. Group 1: One Awesome Engineering

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1 ECE 495 Project 3: Shocker Actuator Subsystem and Website Design Group 1: One Awesome Engineering Luquita Edwards Evan Whetsell Sunny Verma Thomas Ryan Willis Long I. Executive Summary The main goal behind Project 3 was the design and implementation of an actuator subsystem that could be utilized in our overall Shocker robot design for Project 6. The actuator subsystem was designed around the problem of allowing our robot range of motion around the z-axis. In having this degree of motion, our Shocker robot should be able to handle with ease, any angle changes in any wire path that it is presented. Alongside the creation of the actuator subsystem, a corresponding website was developed in order to house all of our respective engineering documents for each specific design project. The overall lesson that we all learned is there a mighty big gap between designing an idea and actually implementing it.

2 II. Engineering Requirements Customer Requirements Accuracy Engineering Requirements Need the servo motor to move smoothly at specified angles Test Verify through measurement that the servo motor moved to the correct angle Cost Parts costs < $300 budget Parts Costs < $300 budget Degrees of Rotation Servo motor is able to rotate 180 degrees Test the maximum and minimum rotation angles Product Life Span Rotation Velocity Size Requirement xpc and Quanser Board interface Operation time greater than 100 usage cycles Servo motor's rotational speed needs to be ms/degree Servo motor needs to be mountable on overall robot design Servo motor needs to be controlled by the xpc / Quanser board connection Verify that the servo motor is still operational after 100 or so uses Verify the speed of the servo motor to be a the calculated speed The servo motor is mountable and does not hinder operation Servo motor control will be executed by the xpc interface The engineering requirements necessary for the creation and implementation of our actuator subsystem centered on the idea of having perfect z-axis motion. Without such perfect accuracy in our servo motor, there could be an angle measure in a wire path that the overall robot will not be able to navigate. Page 2

3 III. Actuator Subsystem Design The HS-311 servo motor rotates when an analog square pulse is received on the input signal pin. Depending on the pulse s length, the servo motor will rotate to a corresponding degree angle. In order to properly manipulate the servo motor, we had to calculate both the minimum and maximum pulse widths that could still motivate the motor. These calculations and resultant command pulses can be seen below in Figures 1, 2, and 3. Once the extreme angle values were known, we were able to calculate the necessary command pulses in order to obtain a degree range from A sample calculation is shown below. Servo Motor Calculation Example: 30 turn = (30* ms) ms [our initial value] = ms Max and Min PWM for servo motor 0 degree = 0.55ms 90 degree = 1.52ms 180 degree = 2.48ms Servo Motor Calculation (Specific Degree) 180 degree turn = 2.48ms ms = 1.93ms 1 degree = 1.93/180 = ms Square Command Pulses: Figure 1: PWM for 0 turn of Servo Motor Page 3

4 Figure 2: PWM for 90 turn of Servo Motor Figure 3: PWM for 180 turn of Servo Motor Page 4

5 Figure 4: Servo Motor Circuit Diagram As shown above in Figure 4, we have an amplifier component increasing our command signal to the necessary 5V in order to properly drive our servo motor. The servo motor is grounded through a ground pin, while the signal pin is connected to the third analog output port of the Quanser board. The Quanser board is able to control the servo motor by inputting the appropriate square pulse in order to move to the desired angle. Page 5

6 IV. Mechanical Design Details Figure 5 below is a picture of our HS-311 servo motor that we will use in order to rotate the Shocker game fork around the z-axis. The servo motor has three wires that are used to in order to interface with it. The red wire is Vcc or the power supply, the black wire is the grounding line, and the yellow wire is the signal line. The HS-311 motor runs on 5.0 V DC, which we were able to obtain in lab by linking the command signal from the Quanser board to a linear voltage amplifier. By amplifying the command signal from its much lower 1.0V, we were able to have enough power in order to drive the servo motor. Once all these wire and pin connections were in place, the servo motor was ready to be controlled by our Simulink control program. Figure 5: HS-311 Servo Motor Figure 6: Simulink Control Diagram Our Simulink control diagram works by first multiplying the desired degree measure with the appropriate pulse width. Then this product is compared to the current angle that the servo motor is sitting on. If the angle measure is not the desired one, then the program will keep adjusting the angle measure until it is correct. Once the correct pulse width is determined, the program will output a command signal that will be amplified and feed into the servo motor signal pin to control the motor. Page 6

7 V. Prototype Demonstration and Testing Our servo motor worked exactly as we expected being able to have a full range of motion around the z- axis. The servo motor was correctly interfaced with the Quanser board, allowing for precise rotation to any specified angle. We tested multiple angle measures and the servo motor was able to successfully turn to all of them. The servo motor s range is approximately from Our actual actuator prototype is shown below in Figure 6. Figure 6: Actuator Prototype Page 7

8 VI. Conclusion In summary, for Project 3 we utilized a servo motor in order to construct an actuator subsystem for our overall Shocker robot. This servo motor is controlled by the Quanser board through an analog port that is governed by our Simulink control program. This program allows us to command our servo motor in order to move to any desired angle from The design of our actuator subsystem was completed with adherence to our engineering requirements as desired by our customer. This actuator subsystem will most likely end up in our final design for the Shocker project as the z-axis component, which will allow us to handle any angle variations a wire path may present. Team Website: VI. References [1] T. Burg. (2014, March 3). Clemson ECE 495 Project 3 Instructions [Online]. Available: [2] (2014, March 3). Hitec HS-311 Standard [Online]. Available: Page 8

9 ECE495 Research Project 3 Group Name and Members: Score Pts ABET Outcomes 5 General Report Format - Professional Looking Document g a) Fonts, margins (11pt, times new roman, single spaced. 1" margins all sides). b) Spelling and grammar are correct c) Layout of pictures all figures have captions and are referenced in the text d) Follows the page limitations below. e) References. Use IEEE reference format. 5 Page 1: Title, Group Name, Group Members, and Date g Executive Summary (1 well written paragraph) Provide an overview of this project. Briefly what did you do and what did you learned. 20 Page 2: Engineering Requirements (~1 page) b Considering only the Sensor subsystem, make a three column table that lists Customer Requirements in the first column, the resulting Engineering Requirements in the second column, and the third column describes the Tests that will be done on the prototype to verify that your design meets each requirement. Note: One customer requirement may branch to multiple engineering requirements. The following should be a narrative report that describes your design decisions and final design, e.g., don t just have a flowchart without text that explains it. 20 Pages 3-4: c Electrical Design Details (~2 pages) Describe the system including: a) Calculations b) Simulation Results c) Circuit schematics Mechanical Design Details (~1 page) a) Assembly drawings 10 Pages 5: Prototype Demonstration and Testing (1 page) b Build a physical prototype that demonstrates that your design will meet all of the customer requirements. Present the results of your testing, which should consist of graphs and explanations. 5 Page 6: Conclusion (1 page) g Tell the Customer that you have completed the design, it achieves the desired objectives as demonstrated in the prototype testing (use the specific metrics defined in your testing plan), and that your design is complete and they can proceed to manufacturing. 15 Laboratory demonstration of your prototype b 20 General Format of Website a) Aesthetics b) Completeness a. Included the Team Description - No personal information that would be embarrassing to you or your teammates. b. Included Report 1. c. Outline of future sections c) Use of Graphics d) All links relative to starting directory so that it can be moved to ECE site. g Page 9

10 Follow the website guidelines, including, accessibility compliance, at Page 10