MAE 512 Final Project Presentation Design for the front linkage of a shrimp wheeled robot Rob Desjardins Mark Szymanski Christopher Wirz

Abstract In this project, the parameters of a four-bar linkage on the front of a Shrimp platform will be optimized to climb over obstacles of given height 2H, 4H, and 6H. In this project, the parameters of a four-bar linkage on the front of a Shrimp platform will be optimized to climb over obstacles of given height 2H, 4H, and 6H. Candidate parameters were generated using the synthesis and analysis equations presented in lecture, minimizing peak torque and torque fluctuations. Candidate parameters were generated using the synthesis and analysis equations presented in lecture, minimizing peak torque and torque fluctuations. These parameters were then tested using SolidEdge / Dynamic designer and MATLAB for further evolution of the design. These parameters were then tested using SolidEdge / Dynamic designer and MATLAB for further evolution of the design.

Design Procedure (flow chart)

Our task was to design a mechanism capable of moving from point A to point B in the diagram below. Our task was to design a mechanism capable of moving from point A to point B in the diagram below.

Procedure: We first drew a simple diagram to represent the front end of the shrimp. We first drew a simple diagram to represent the front end of the shrimp.

Synthesis equations were developed Synthesis equations were developed This gave us a good initial guess for R values This gave us a good initial guess for R values The goal is to minimize the value of (r1+r2+r3+r4+r5+r6) by varying the following parameters:

Also, loop closure equations were analyzed and differentiated for our case. Also, loop closure equations were analyzed and differentiated for our case. This allowed us to obtain equations for the velocities and accelerations of the various points and links. This allowed us to obtain equations for the velocities and accelerations of the various points and links.

Force Analysis The forces on the aforementioned 4-bar were also analyzed. The forces on the aforementioned 4-bar were also analyzed. The diagrams below show the conventions used for the analysis. The diagrams below show the conventions used for the analysis.

Sum of the forces in the X Sum of the forces in the Y Sum of the moments about the center of mass

Additional Relations

Force Equation Matrix 18 equations, 18 unknowns… 18 equations, 18 unknowns…

Finding Mass For T6061 Aluminum, the density of the material is 2.7g/cc For T6061 Aluminum, the density of the material is 2.7g/cc The cross section area is 1cm^2 The cross section area is 1cm^2 where is in cm. where is in cm. Finding Moment of Inertia

Initial trial: To begin, a simple 2-point synthesis was performed with the points A and B as given by the project description. To begin, a simple 2-point synthesis was performed with the points A and B as given by the project description. The values for the position of the ground points and the change in angle of r4, r1, and r5 were defined before the analysis was performed. The values for the position of the ground points and the change in angle of r4, r1, and r5 were defined before the analysis was performed.

Initial 2 point Synthesis Approach

Next iteration From this point, a GUI was created in MATLAB to display the path of any given 4-bar mechanism. From this point, a GUI was created in MATLAB to display the path of any given 4-bar mechanism. The GUI allowed any parameter to be varied and output an animation of the 4- bar requested and the force and torque graphs with respect to x-position. The GUI allowed any parameter to be varied and output an animation of the 4- bar requested and the force and torque graphs with respect to x-position.

GUI

Ex: Varying the path by varying R4

Our Best Link Lengths r1 = 30 cm r2 = 60 cm r3 = 20 cm r4 = 65 cm r5 = 55 cm r6 = 33 cm

SolidEdge This final configuration was modeled in SolidEdge for visual purposes. This final configuration was modeled in SolidEdge for visual purposes.

END Questions?