Project 1

DOUBLE-ACTING ACTUATOR MODEL IN SIMULINK USING SIMSCAPE BLOCKS

Aim: Develop a double-acting actuator model using Simscape Multibody and Simscape components. The mechanical system of the cylinder needs to be built using Simscape Multibody library components/blocks, and the hydraulic system needs to be modelled using Simscape library physical components.

Objective:

• The mechanical system of the cylinder needs to be built using Simscape Multibody library components/blocks.
• The hydraulic system needs to be modelled using Simscape library physical components.
• Using The Translational Multibody Interface block connects the Translational Mechanical Converter (IL) blocks to the Prismatic Joint block.

Solution:

One piston and a cylindrical casing characterize double-acting hydraulic cylinders. Hydraulic pressure force is applied over the piston and the end cylinder is expanded when hydraulic oil is delivered to its cap end port. The end side of the piston will be forced out and toward the reservoir as the hydraulic oil at the rod extends.
The direction control valve helps to reverse the hydraulic direction for the returning stroke. The piston retracts as a result of hydraulic oil being supplied to the rod end side during the returning stroke. Oil is directed toward the reservoir when the piston cap end retracts. Consequently, the hydraulic actuator with double action functioned in both directions.

Building the mechanical system of the cylinder using Simscape Multibody library components/blocks.

• To model the cylinder and piston, you can use the Revolved Solid (Simscape Multibody) and Cylindrical Solid (Simscape Multibody) blocks.
• To provide the translational degree of freedom for the piston, use a Prismatic Joint (Simscape Multibody) block.

The overall model of a Double-Acting Actuator using Simscape Multibody and Simscape components.

Building the hydraulic system using Simscape library physical components.

• Using two Translational Mechanical Converter (IL) blocks to model the chambers A and B of the cylinder.
• A Translational Multibody Interface block connects the Translational Mechanical Converter (IL) blocks to the Prismatic Joint block.

Bottom Chamber:

Head Chamber:

Stroke Length: 0.45 m

Hydraulic Circuit:

Valve Control:

• Here valve control unit is referred from Hydraulic Interface-Dump Trailer with Hydraulic Cylinder
• https://in.mathworks.com/help/sm/ug/hydraulic-interface-dump-trailer-with-hydraulic-cylinder.html
• Reference model sm_dump_trailer

Valve:

Isothermal Liquid Properties (IL) & Pressure Source (IL):

Prismatic Joint:

A prismatic joint is frequently referred to as a slider, as in "crank-slider linkage." This is an idealized representation of a kinematic pair that describes how motions are restricted within machines.

Building Cylinder:

Bottom Cap:

Barrel:

cross-section= [0.08, 0.5/2; 0.08, -0.5/2; 0.1, -0.5/2; 0.1, 0.5/2] m

Head Cap:

cross-section= [0.04, 0.05/2; 0.04, -0.05/2; 0.1, -0.05/2; 0.1, 0.05/2] m

Building Piston:

Piston:

Rod:

Valve Input:

Scope Result:

In the plot, the Valve input and Position signal are plotted with respect to the time(s).

Accordingly, as the position signal changes piston is moved.

Mechanics Explorer Simulated Result:

• Here, red coloured solid is the piston which is connected to the blue-coloured rod.
• Using the controller valve the fluid is passed through the hydraulic valve to the mechanical system due to which there is a change in the position of the piston.

Conclusion:

In this case, Simscape Multibody library blocks and components are used to build the cylinder's mechanical system, while Simscape library physical components are used to model the hydraulic system.

The Signal Builder block provides the valve's input signal.

Applications for double-acting cylinder systems are numerous. For instance, a scissor hoist mechanism on a dump trailer can be operated by a double-acting cylinder to raise and lower the dump bed.

The translational multibody interface block connects the mechanical and hydraulic subsystems of the scissor hoist, which are located behind the mask of the double-acting hydraulic cylinder block.