A new dynamic model for friction is proposed in this paper. The model captures most of the friction behavior observed experimentally, including the Stribeck effect, hysteresis, spring-like characteristics for stiction, and varying break-away force. The model's properties relevant to control design are analyzed and simulated. New control strategies, including a friction observer, are explored, and stability results are presented. Friction is an important aspect of many control systems, affecting tracking errors, limit cycles, and undesired stick-slip motion. Model-based friction compensation techniques are needed to predict and compensate for friction. Classical friction models, such as Coulomb and viscous friction, are insufficient for high precision positioning and low velocity tracking. A better description of friction phenomena for low velocities and when crossing zero velocity is necessary. The Dahl model, which describes the spring-like behavior during stiction, is a well-known model but does not include the Stribeck effect. An attempt to incorporate the Stribeck effect into the Dahl model was made, but the Stribeck effect was only transient. The proposed model combines the Dahl effect with arbitrary steady-state friction characteristics, including the Stribeck effect. It is shown to be useful for various control tasks. The model is characterized by the function g and parameters σ₀, σ₁, and σ₂. The function σ₀g(v) + σ₂v can be determined by measuring the steady-state friction force when the velocity is held constant. A parameterization of g that describes the Stribeck effect is given. The model is characterized by six parameters: σ₀, σ₁, σ₂, FC, FS, and vs. The model's properties are explored, including dissipativity. The model is shown to be dissipative with respect to the function V(t) = ½z²(t). Linearization in the stiction regime shows that the system behaves like a damped second-order system. The model's behavior is investigated in typical cases, including presliding displacement, frictional lag, varying break-away force, and stick-slip motion. The model is applied to servo problems, showing that it predicts limit cycle oscillations in servos with PID control. A friction observer is designed to estimate the friction force and compensate for it. The observer error and control error asymptotically go to zero when the parameters are known. The model is also used for velocity control, showing that the observer error and velocity error asymptotically go to zero when the parameters are known. The model is shown to capture various friction phenomena, including hysteresis, spring-like behavior in stiction, and varying break-away force. The model is simple yet captures most friction phenomena of interest for feedback control. It can be used in simulations of systems with friction.A new dynamic model for friction is proposed in this paper. The model captures most of the friction behavior observed experimentally, including the Stribeck effect, hysteresis, spring-like characteristics for stiction, and varying break-away force. The model's properties relevant to control design are analyzed and simulated. New control strategies, including a friction observer, are explored, and stability results are presented. Friction is an important aspect of many control systems, affecting tracking errors, limit cycles, and undesired stick-slip motion. Model-based friction compensation techniques are needed to predict and compensate for friction. Classical friction models, such as Coulomb and viscous friction, are insufficient for high precision positioning and low velocity tracking. A better description of friction phenomena for low velocities and when crossing zero velocity is necessary. The Dahl model, which describes the spring-like behavior during stiction, is a well-known model but does not include the Stribeck effect. An attempt to incorporate the Stribeck effect into the Dahl model was made, but the Stribeck effect was only transient. The proposed model combines the Dahl effect with arbitrary steady-state friction characteristics, including the Stribeck effect. It is shown to be useful for various control tasks. The model is characterized by the function g and parameters σ₀, σ₁, and σ₂. The function σ₀g(v) + σ₂v can be determined by measuring the steady-state friction force when the velocity is held constant. A parameterization of g that describes the Stribeck effect is given. The model is characterized by six parameters: σ₀, σ₁, σ₂, FC, FS, and vs. The model's properties are explored, including dissipativity. The model is shown to be dissipative with respect to the function V(t) = ½z²(t). Linearization in the stiction regime shows that the system behaves like a damped second-order system. The model's behavior is investigated in typical cases, including presliding displacement, frictional lag, varying break-away force, and stick-slip motion. The model is applied to servo problems, showing that it predicts limit cycle oscillations in servos with PID control. A friction observer is designed to estimate the friction force and compensate for it. The observer error and control error asymptotically go to zero when the parameters are known. The model is also used for velocity control, showing that the observer error and velocity error asymptotically go to zero when the parameters are known. The model is shown to capture various friction phenomena, including hysteresis, spring-like behavior in stiction, and varying break-away force. The model is simple yet captures most friction phenomena of interest for feedback control. It can be used in simulations of systems with friction.