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Richard Vetter – AMS SolutionsMark Stirn – Bosch USA
September 29, 2016
1
University of British Columbia (1998 – 2004)Masters of Applied Science in Controls Systems
Newnes Machine (2005 – 2008)Primary Breakdown Controls Group
AMS Solutions (2008 ‐ 2016)One of the Founding PartnersControls / IntegrationSpecialize in Hydraulic and Electric Motion ControlBosch Rexroth System Integrator
Introduction –Richard Vetter
2
Introduce the “problem” with Traditional Hydraulic System DesignMotion Control issues related to non‐ideal hydraulic pressure control Integration of the Motion Controller and a “Smart” HPU can provide near‐perfect Hydraulic Pressure RegulationBosch Sytronix Technology and its benefits over a Traditional HPU
PerformanceEnergy Savings
Presentation Outline
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Hydraulic AxisCylinderProportional Valve
Hydraulic Power UnitAccumulatorPressure Compensated Pump
Traditional Hydraulic System
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“Simster” Simulation2.5” Cylinder100 LPM Pressure Compensated Pump2200 PSI Setpoint10L vs 20L Accumulator
Traditional Hydraulic System
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1500
1600
1700
1800
1900
2000
2100
2200
2300
‐10
0
10
20
30
40
50
0 1 2 3 4 5 6 7 8 9 10
System Pressure Drop
Cylinder Position [in] Cylinder Velocity [in/s] Accumulator Pressure 10L [psi]
15” Move
20 in/sec270 psi Drop
Pressure Compensated Pumps require a pressure drop to generate flow
Rarely sized to meet the Peak Flow requirements of the motion control system
Pumps are typically sized for Average FlowRely on accumulators to supply Peak Flow
Traditional Hydraulic System Design
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‐60
‐40
‐20
0
20
40
60
80
100
120
1500
1600
1700
1800
1900
2000
2100
2200
2300
0 1 2 3 4 5 6 7 8 9 10
Flow Rates
Accumulator Pressure 10L [psi] Valve Flow Rate [l/min] Accumulator Flow Rate [l/min] Pump Flow Rate [l/min]
53 LPM
96 LPM68 LPM
Accumulator Charging@ 45 LPM
Too much pressure drop?Add accumulators
Larger accumulators means:Longer charge timesLower “steady state” pressure
Traditional Hydraulic System Design
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1500
1600
1700
1800
1900
2000
2100
2200
2300
‐10
0
10
20
30
40
50
0 1 2 3 4 5 6 7 8 9 10
System Pressure Drop
Cylinder Position [in] Cylinder Velocity [in/s] Accumulator Pressure 10L [psi] Accumulator Pressure 20L [psi]
15” Move
20 in/sec270 psi Drop220 psi Drop
Larger Accumulator = Lower Pressure Drop but Longer Recovery Time
Variable System Pressure is the Enemy of Motion ControlVariable Pressure = Sub‐Optimal Tuning
Increased Following ErrorIncreased Axis “In‐Position” Time
The Problem –Variable System Pressure
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What is an “acceptable” pressure drop?“It’s fine”“There’s nothing wrong”“It works”
Control System is now able to squeeze the last milliseconds out of the machineAt 500 FPM:
10ms = 1” 16’ Log + 8’ Gap = 288” of travel per piece1” = ~ 0.35%
Pressure Drop & Sub‐Optimal Tuning
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The Solution – Integrate HPU & Motion Controller
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MotionController Position Feedback
Proportional Valve
AnalogPressure Sensor
Fixed DisplacementPumpVariable Speed Drive
Pressure FeedbackHPU
Controller
FlowCommand
(1ms updates)
The Solution – “Smart” HPU
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MotionController
Variable Speed Drive
Position Feedback
Proportional Valve
Pressure Feedback
Ethernet
High SpeedCommunications
HPUController
AnalogPressure Sensor
Fixed DisplacementPump
Performance –Before Upgrade
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420 PSIDrop
0.240s Recovery
Performance –After Upgrade
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20 PSIRipple
‐0.2
0
0.2
0.4
0.6
0.8
1
‐5
0
5
10
15
20
25
0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000
Command Velocity Position Error Before Position Error After
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Log Turner Motion –Before & After
On a 10” Diameter Log, 0.100” of Following Error = 1 degree of Turn Error
0.600” Peak Error
0.110” Peak Error
22 Inches / Second
0.020” Error
Improved Diagnostics
Confidential – AMS Solutions Inc. 18
System Leakage MonitoringLine Break Detection
Confidential – AMS Solutions Inc. 19