## MCE 260 Fall 2015 Homework 4, due September 22, 2015. PRESENT CLEARLY HOW YOU DEVELOPED THE SOLUTION TO THE PROBLEMS Each problem is worth up to 5 points. Points are given as follows: 5 points: Work was complete and presented clearly, the answer is correct 4 points: Work was complete, but not clearly presented or some errors in calculation 3 points: Some errors or omissions in methods or presentation 2 points: Major errors or omissions in methods or presentation 1 point: Problem was understood but incorrect approach was used DO SOMETHING WITH LINKAGES 1. (5 points) Fig 4-16b shows a Stephenson 6-bar linkage. Assume that the linkage is driven by a constant speed motor on the fixed pivot of link 7. Draw this linkage schematically (dimensions are not important). The link numbering and vector loops are already defined in Fig 4-16b. Add symbols for the angles θ2… θ8 and the lengths L2… L8 to the Figure. 2. (5 points) There are two vector loops (1-2-3-4, and 4-5-6-7-8). Write the vector loop equations as separate X and Y equations for each loop. 3. (5 points) Identify the unknowns that must be solved for doing position analysis. Make sure that the number of unknowns is the same as the number of equations. Hint: “links” 3 and 5 are both on the (rigid) coupler, so there is a simple relationship between the two angles. 4. (5 points) Write the vector loop equations for the inverted crank-slider (Fig. 4-13). Identify the two unknowns that must be solved when it is driven by the slider joint, which means that length b is a known input (as in the hydraulic excavator). Write expressions for the elements of the 2×2 Jacobian matrix. 5. (5 points) Modify the Matlab code fbpos1vec.m to solve the position analysis problem for this system. You may choose the dimensions and the input (probably best to make this similar to Fig 4-13). Show the lines of Matlab code that you changed (and no other lines) and show the values for the two unknowns that you solved. Page 1 of 1

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