Soil Mixer 2019/Controller

This page includes information about the entire electromechanical hydraulic control system for the soil mixer. This is a variant of CEB Press Controller v19.01

Controller Requirements

• Needs to switch a double acting cylinder while running a hydraulic motor
• Needs to cycle a dc motor for cement dosing
• Water mister solenoid

Electronics

• Mega 2560
• Relay Shield (3A)
• External Relays boards for >3A
• Fused Battery Connection
• High Pressure Switch

Hydraulics

Hydraulic Calculations

Hydraulic Cylinder Volumes. 2.5x12x1.25 Cylinder
Cap End Volume:((2.5in)/2)^2 * 3.14 * 12in =58.875 cu in
Rod Volume: ((1.25in)/2)^2 * 3.14 * 12in = 14.71875 cu in
Rod End Volume = 58.875 cu in - 14.71875 cu in = 44.15625‬ cu in

Cylinder Travel Speeds

Flow Rate	Extend Time	Retract Time
5 GPM	3.06s	2.29s
7.5 GPM	2.04s	1.53s
10 GPM	1.53s	1.15s
12.5 GPM	1.22s	0.92s
15GPM	1.02s	0.76s

Hydraulic Diagram

edit

Hydraulic Circuit Simulation

20Nm Load on Motor

Check out these videos first. 20nm load derived on mixer main page in design review section

Older simulations: /Hydraulic Simulation Archive

Soil Mixer Circuit Simulations

Series Circuit	Sequence Valve Circuit Closed Center Valve	Sequence Valve Circuit Open Center Valve
13.25 GPM through valve. Motor speed up to 4K RPM on cyl retract. When cylinder bottoms out, fluid has no path to tank and flow stops through the system.	Whereas the third circuit has difficulty retracting the cylinder under heavy motor loads, this circuit has no such condition. Flow rate through motor significantly decreased when cylinder is traveling as all cylinder flow is lost to tank.	If the motor is loaded more than 20Nm(maybe 40Nm, the cylinder cannot retract. I'm not entirely sure why this is yet. If the motor is loaded at 20Nm then the circuit behaves well and all flow from cylinder goes to motor during cylinder travel.