Fundamentals of Engineering High-Performance Actuator Systems Kenneth W. Hummel Author Name
Chapter 1: Introduction...1 1.1 Fundamentals... 2 1.2 Performance... 2 1.3 Loads... 3 1.4 Constraints... 3 1.5 Design Margin... 4 1.6 Environment... 4 1.7 Component Strength... 5 1.8 Component Stiffness............................................. 5 1.9 Reliability... 5 1.10 Maintainability... 6 1.11 Cost... 6 1.12 Summary... 6 1.13 References... 8 Chapter 2: Project Management...9 2.1 Scope... 9 2.2 Requirements... 9 2.3 Schedule... 10 2.4 Cost... 13 2.4.1 Design Cost... 14 2.4.2 Prototype Cost... 15 2.4.3 Production Cost... 17 2.4.4 Operating Cost... 19 2.4.5 Decommissioning Cost... 19 2.4.6 Cost Estimating Techniques... 20 2.5 Risk... 21 2.5.1 Schedule... 22 2.5.2 Cost... 22 2.5.3 Technology... 22 2.5.4 Customer Acceptance... 22 2.5.5 Risk Management... 23 2.6 Project Close Out... 24 2.7 References... 25 v
vi Chapter 3: Requirements Analysis...27 3.1 Performance... 28 3.1.1 Work... 30 3.1.2 Impulse... 31 3.1.3 Momentum... 31 3.1.4 Energy... 31 3.1.5 Power... 32 3.1.6 Equations of Motion... 33 3.1.6.1 Summary... 42 3.1.6.1.1 Velocity... 42 3.1.6.1.2 Acceleration... 43 3.1.6.1.3 Position.............................. 44 3.2 Loads... 46 3.3 Component Stiffness............................................ 49 3.3.1 Linear Stiffness......................................... 49 3.3.2 Rotary Stiffness... 50 3.3.3 Materials... 52 3.4 Component Strength... 53 3.4.1 Yield Strength and Elastic Analysis... 54 3.4.2 Ultimate Strength and Plastic Analysis... 59 3.4.3 Fatigue Strength... 61 3.5 Constraints... 65 3.5.1 Mounting Configuration... 65 3.5.1.1 Pinned Joints................................... 66 3.5.1.2 Simply Supported Joints... 66 3.5.1.3 Fixed Support Joints... 66 3.5.1.4 Joint Combinations... 66 3.5.2 Environment... 67 3.5.2.1 Operation... 67 3.5.2.2 Storage... 67 3.5.2.3 Shipping and Transportation... 68 3.5.3 Pollution... 68 3.5.4 Safety... 68 3.5.4.1 Personnel Safety... 69 3.5.4.2 Machine Safety... 69 3.5.4.3 Environmental Safety... 69 3.5.4.4 Safety Summary... 69 3.5.5 Reliability... 70 3.5.6 Maintenance... 71 3.5.6.1 Preventative Maintenance... 71 3.5.6.2 Repair... 72 3.6 Verification and Validation... 73 3.7 Summary... 73 3.8 References... 73
Chapter 4: Design to Requirements...75 4.1 Performance Allocations... 75 4.2 References... 80 Chapter 5: Power Sources...81 5.1 Hydraulic... 81 5.1.1 Hydraulic Symbols... 81 5.1.2 Power Source... 82 5.1.3 Hydraulic Power Unit... 83 5.1.4 HPU Component Selection... 84 5.1.5 Fluids... 84 5.1.6 Tank or Reservoir... 86 5.1.7 Pumps... 87 5.1.8 Prime Mover... 88 5.1.9 Filters... 88 5.1.10 Accumulators... 89 5.1.11 Heat Exchangers... 91 5.1.12 General Hydraulic Power Unit Valves... 92 5.1.13 High-Performance Actuator Control Valves... 93 5.1.14 References... 94 5.2 Pneumatic Systems... 95 5.2.1 References... 98 5.3 Electric... 98 5.3.1 References... 101 5.4 Actuator Detailed Design... 101 5.4.1 Motor Selection... 101 5.4.1.1 Motor Shaft Loads... 101 5.4.1.2 Motor Torque Requirements... 102 5.4.1.3 Motor Speed Requirements... 104 5.4.1.4 Electric Motor Selection... 104 5.4.1.4.1 AC induction (synchronous) motors... 106 5.4.1.4.2 DC stepper motors... 106 5.4.1.4.3 DC brushless motors... 107 5.4.1.4.4 DC brushed permanent magnet motors... 109 5.4.1.5 Hydraulic Motor Selection... 109 5.4.1.5.1 Gear motors...112 5.4.1.5.2 Vane motors...112 5.4.1.5.3 Gerotor/Geroler motors...113 5.4.1.5.4 Axial and bent axis piston motors...113 5.4.1.5.5 Radial piston motors...114 5.4.1.6 Pneumatic Motors...115 5.4.2 References...116 vii
5.5 Control Element Design and Selection...116 5.6 Linear Actuator Design...116 5.6.1 Cylinders... 121 5.6.1.1 Hydraulic Cylinders... 123 5.6.1.2 Pneumatic Cylinders... 134 5.6.2 Motor and Rack... 135 5.6.3 Screws... 136 5.6.4 Spring Rate for Power Screw Actuators... 144 5.6.4.1 Mounting Structure and Load Structure Stiffness... 144 5.6.4.2 Screw Stiffness... 145 5.6.4.3 Nut Stiffness... 145 5.6.4.4 Total Screw/Nut Stiffness....................... 146 5.6.4.5 Bearings... 147 5.6.5 Screw Critical Speed... 147 5.6.6 Electric Solenoids... 149 5.6.7 Electric Linear Motors... 152 5.6.8 References... 155 5.7 Rotary Actuator Design... 156 5.7.1 Direct Drive Motors... 156 5.7.2 Gear Boxes... 156 5.7.3 Mechanical Mechanisms... 160 5.7.4 Racks... 161 5.7.5 References... 163 5.8 Feedback Systems... 163 5.8.1 Sensor Type... 163 5.8.1.1 Rotary Sensors... 164 5.8.1.2 Linear Sensors... 165 5.8.1.3 Inertial Sensors... 167 5.8.2 Sensor Location... 169 5.8.3 Actuator Components to Stop/Hold a Load... 170 5.8.4 References... 172 5.9 Verification and Validation... 172 Chapter 6: Prototyping...173 6.1 Fabrication... 173 6.2 Assembly... 175 6.3 Prototype Verification and Validation... 176 Chapter 7: Verification and Validation...177 7.1 Engineering Judgment... 177 7.2 Comparison... 178 7.3 Analysis... 178 7.4 Testing... 178 viii
Chapter 8: Production...181 Bibliography... 183 Appendix A: Hydraulic Symbols... 187 Training Supplement Problems by Chapter... 193 Chapter 1 Problems... 193 Chapter 2 Problems... 193 Chapter 3 Problems... 194 Chapter 4 Problems... 197 Chapter 5 Problems... 197 5.1 Problems... 197 5.2 Problems... 198 5.4 Problems... 198 5.6 Problems... 198 5.7 Problems... 200 5.8 Problems... 201 Chapter 7 Problems... 201 About the Author... 203 Index... 205 ix