The Halloween decorations designed by project teams 4, 5 and 6 can be seen in the video
Students in my MAE 245 Advanced Kinematic Synthesis class have designed Halloween decorations using a four-bar linkage by itself or in combination with a parallelogram or pantograph linkage. You can see the work of teams 1, 2 and 3 in the video:
Here are the solid models of some of the walkers designed by UC Irvine students in my Spring 2019 course MAE 183 Kinematic Synthesis of Mechanisms.
Walker Group 1
Walker Group 2
Walker Group 4
Walker Group 6
Walker Group 8
Walker Group 9
Walker Group 10
This is an animation of the leg mechanism for a mechanical walker designed using function generators to drive the hip and knee joints. A second parallelogram linkage is used to construct a translating leg that allows placement of the foot trajectory where ever the designer chooses.
This is a series of four videos that show how to:
- Specify three positions for the foot of a leg consisting of a hip and knee joint;
- Use three position synthesis to design a four-bar function generator to guide the hip joint;
- Then use three position synthesis to design a second four-bar function generator to guide the knee joint;
- And finally assemble the linkage to determine the trajectory of the foot. Adjusting the lengths of the leg segments, the position of the hip, the specified positions of the input cranks, and the position of the coupler attachments to the input cranks vary the resulting foot trajectory. An example leg mechanism is shown at the end of this video.
Part 1:4 Setting up the design
Part 2:4 Synthesis of the hip function generator.
Part 3:4 Synthesis of the knee function generator.
Part 4:4 Assembly of the leg mechanism, exploration of design variations, and an example final leg design.
The graphical construction of a four-bar function generator that coordinates three input and three output angles is presented in the video below. It is possible to coordinate as many as five input-output angles, but this requires numerical calculations using software like our MechGen FG iOS application.
Our MechGen FG iOS application provides five position synthesis for four-bar linkages. A Demo of the iPad version is provided below. It is also available on the iPhone.
The graphical construction of a four-bar linkage that coordinates two positions of an input crank with two positions of an output crank is presented in this video using Geogebra.
A linkage that coordinates the values of input and output angles is called a function generator. It is possible to design a four-bar linkage to coordinate as many as five input and output angles. However, this requires numerical calculations using software such as our MechGen FG iOS application.
This video adds a skew pantograph to a four-bar linkage in order to reorient and change the size of the coupler curve. The result is a six-bar leg mechanism with a foot trajectory that is a scaled version of the original coupler curve.
In this video, we start with a four-bar linkage and coupler curve and construct an additional crank with a floating link connected to the coupler point. This floating link becomes the leg of the Klann-style leg mechanism. Adjustment of the dimensions of the added links shapes the foot trajectory.