Operating Principles
Pneumatic cylinders convert potential energy of compressed gas into mechanical linear force. Gas compressibility creates unique dynamic stiffness and velocity behavior.
Key Instructional Concepts
- Meter-Out Speed Control: Throttling exhaust air (rather than inlet air) creates an opposing back-pressure cushion that prevents lunging, stick-slip, and erratic motion under varying loads.
- Differential Force Output: Due to rod area reduction ($A_{rod} < A_{cap}$), extension force is higher than retraction force at identical supply pressure ($F_{ext} = P \cdot A_{cap}$, $F_{ret} = P \cdot A_{rod}$).
- End-Position Cushioning: Trapping a volume of air in a small cushion pocket near end-of-stroke forces exhaust through a needle valve, absorbing kinetic energy smoothly ($E_k = \frac{1}{2}m v^2$).
Governing Equations
- Cap Area (A_cap)π/4 · D² = 8.04 cm²
- Rod Area (A_rod)π/4 · (D² - d²) = 6.91 cm²
- Net Drive ForceP_A A_cap - P_B A_rod - F_fric
- Air Mass Flowṁ = C · P_in · ρ_0 · √(T_0/T)