Tuned mass damper

Abstract

A tuned mass damper (TMD) is disclosed. The TMD includes a mass and at least one spring connected to the mass. The at least one spring has a spring stiffness. The TMD also includes a damper for damping the motion of the mass, the damper having a damping coefficient. At least one of the spring stiffness and the damping coefficient is adjustable during vehicle operation to modify the frequency damped by the TMD.

Description

Tuned Mass Damper Embodiments of the present invention generally relate to damping component frequencies. During normal operation, a vehicle is propelled through terrain. During this action, the vehicle may generate unwanted oscillations and / or frequency vibrations that fall within frequency ranges known to cause increased human stress and fatigue. Sometimes, the unwanted oscillations and / or frequency vibrations are vehicle characteristic-based and can thus be considered during design and construction. However, when the vehicle traverses different terrains, new and unaccounted-for oscillations and / or frequency vibrations of different wavelengths may occur. These new and unaccounted-for oscillations and / or frequency vibrations can quickly cause fatigue, stress, etc. to the vehicle user. Due to the almost infinite variations and combinations of vehicle body types, terrain types, weather, location, vehicle modifications, etc., it is impossible to anticipate and address these new and unaccounted-for oscillations and / or frequency vibrations during design and / or manufacturing. Therefore, designers and constructors are constantly looking for ways to address both the accounted-for oscillations and / or frequency vibrations as well as the unaccounted-for oscillations and / or frequency vibrations. 100: Tuned Mass Damper (TMD) 1000: Multi-modal TMD System 101: Mass 1010: Shock Absorbing Component 1015: Semi-active Damping Component 1016, 515, 815: Fluid 102: Spring 1020: Internal Floating Piston (IFP) 105: Event 1050: evol 1065, 605, 705, 805, 905: Chamber 1070, 710: Valve 12: Pivot Point 15: Rear Axle 18: Axle 24: Frame 26: Swing Arm 28: Front Wheel 30: Rear Wheel 300, 350: Graph 301, 305, 351, 355: Curve 32: Seat 33: Seat Post 34: Front Fork Assembly 35, 5: Sensor 36: Handlebar 38: Rear Shock Absorbing Component 39: Controller 400,425: Table 50: Vehicle 505: Cylindrical housing 612: End portion 620: Small volume 650: Medium volume 675: Large volume 730: Compressor 735: Exhaust valve 75: Tuned mass damper (TMD) system 823: Flow path 825: Active valve 93: Direction 933: Sliding surface 934: Magnet stack A - A: Portion Aspects of the present invention are illustrated by way of example and not limitation in the figures, in which: Figure 1A is a perspective view of a vehicle having at least one frequency - adjustable tuned mass damper (TMD) according to an embodiment. Figure 1B is a perspective view of a frequency - adjustable TMD system on a vehicle according to an embodiment. Figure 2A is a schematic view of a vehicle according to an embodiment. Figure 2B is a schematic view of a frequency - adjustable TMD added to a vehicle according to an embodiment. Figure 3A is a graph of amplitude versus frequency of a front fork assembly according to an embodiment. Figure 3B is a graph of position versus time for the x - axis position of a front fork assembly during forced vibration according to an embodiment. Figure 4A is a table of equations for determining the appropriate mass, damping coefficient, and spring stiffness of a TMD according to an embodiment. Figure 4B is an additional calculation table for a TMD according to an embodiment. Figure 5A is a front view of a handlebar having a frequency - adjustable TMD according to an embodiment. Figure 5B is a cross - sectional view of a frequency - adjustable TMD optimized to fit within a handlebar according to an embodiment. Figure 6A is a front - view cross - section of a frequency - adjustable TMD having semi - active variable spring stiffness and a small - volume configuration according to an embodiment. Figure 6B is a front - view cross - section of a frequency - adjustable TMD having semi - active variable spring stiffness and a medium - volume configuration according to an embodiment. FIG. 6C is a front cross-sectional view of a frequency adjustable TMD 100 having a semi-active variable spring stiffness and a general volume configuration according to an embodiment. FIG. 7A is a front cross-sectional view of a frequency adjustable TMD having a variable spring stiffness based on a manually variable pressure configuration according to an embodiment. FIG. 7B is a front cross-sectional view of a frequency adjustable TMD having a semi-active variable spring stiffness based on a semi-active pressure variable configuration according to an embodiment. FIG. 8A is a front cross-sectional view of a frequency adjustable TMD having a semi-active controlled damping coefficient according to an embodiment. FIG. 8B is a cross-sectional view of the A-A portion of FIG. 8A according to an embodiment. FIG. 9A is a perspective view of a frequency adjustable TMD having a semi-active controlled damping coefficient according to an embodiment. FIG. 9B is a cross-sectional view of a frequency adjustable TMD having the semi-active controlled damping coefficient of FIG. 9A according to an embodiment. FIG. 10A is a schematic diagram of a multi-modal TMD system according to an embodiment. FIG. 10B is a schematic diagram of another multi-modal TMD system according to an embodiment. FIG. 10C is a schematic diagram of another multi-modal TMD system according to an embodiment. Unless otherwise specified, the drawings referred to in this specification should be understood not to be drawn to scale. The detailed description set forth below in connection with the drawings is intended as a description of the various embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. Each embodiment described in the present invention is provided only as an example or illustration of the invention and should not be construed as being preferred or advantageous over other embodiments. In some instances, well-known methods, procedures, elements, and circuits are not described in detail so as not to unnecessarily obscure aspects of the invention. User experience is often severely affected by the dynamic responses and structural characteristics of one or more components of the vehicle they are operating. For example, the dynamic responses (resonance frequencies and damping ratios) and structural characteristics (stiffness and strength) of different components are not always isotropic, and different frequencies will affect different parts of the human body in different ways. The embodiments disclosed herein provide a tuned mass damper (TMD) that can respond to various frequencies transmitted to various components during vehicle use. That is, the TMD can reduce and / or change the expected and new vibration and / or resonance frequencies that occur during vehicle use. In doing so, the TMD can provide a better user experience in various usage scenarios. In addition, various embodiments of the TMD disclosed herein are configured to improve grip by reducing unwanted oscillations in the pressure on the ground, improve suspension performance by eliminating the increased static friction during the back-and-forth oscillation of the fork, and capture energy. Referring now to FIG. 1A, a perspective view of a vehicle 50 according to an embodiment is shown, the vehicle 50 having a frequency-tunable TMD 100 coupled thereto. In one embodiment, the vehicle 50 is a bicycle. For clarity, a bicycle is used as an example vehicle 50. However, in another embodiment, one or more frequency-tunable TMDs may be used on one or more of the following various vehicles: such as but not limited to bicycles, motorized bicycles, motorcycles, watercraft (e.g., boats, jet skis, personal watercraft (PWC), etc.), snowmobiles, unicycles, multi-wheel vehicles, side-by-side road and / or off-road vehicles, aircraft, personal light electric vehicles (PLEV), etc. Generally, a motorized bicycle may include a bicycle with an internal combustion engine, an electric bicycle (e-bike), a hybrid electric and combustion bicycle, a hybrid motor and pedal-powered bicycle, etc. In one embodiment, one or more frequency-tunable TMDs may be used with a device including a suspension (instead of or in addition to the vehicle 50) such as but not limited to an exoskeleton, a seat frame, a prosthesis, an orthosis, a suspension floor plate, etc. In one embodiment, the vehicle 50 has a frame 24 with a suspension system that includes a swing arm 26 that can move relative to the rest of the frame 24 during use; this movement is particularly allowed by the rear shock assembly 38. The front fork assembly 34 also provides a suspension function via a shock assembly in at least one fork leg. In one embodiment, vehicle 50 is a full-suspension bicycle. In another embodiment, vehicle 50 has only a front suspension and no rear suspension (e.g., hardtail). In various embodiments, vehicle 50 can be a road bicycle, a mountain bicycle, a gravel bicycle, an electric bicycle (e-bike), a hybrid bicycle, a motorcycle, etc. In one embodiment, swing arm 26 is pivotally attached to frame 24 at pivot point 12. Although pivot point 12 is shown in a particular position, it should be understood that pivot point 12 can be in different positions. In a hardtail bicycle embodiment, there will be no pivot point 12. In one embodiment of a hardtail bicycle, frame 24 and swing arm 26 will be formed as a fixed frame. Vehicle 50 includes a front wheel 28, which is coupled to a front fork assembly 34 via an axle 18. In one embodiment, a portion of the front fork assembly 34 (e.g., the steering tube) passes through the bicycle frame 24 and is coupled to handlebars 36. In doing so, the front fork assembly 34 and the handlebars 36 are rotatably coupled to the frame 24, thereby allowing a rider to steer the vehicle 50. In one embodiment, the frequency-adjustable TMD 100 is located within the steering tube. In one embodiment, vehicle 50 includes a rear wheel 30, which is coupled to swing arm 26 at a rear axle 15. A rear shock assembly 38 is positioned between the swing arm 26 and the frame 24 to provide resistance to the pivotal movement of the swing arm 26 about pivot point 12. In one embodiment, a seat 32 is connected to the frame 24 via a seat post 33. In one embodiment, the seat post 33 is a dropper seat post. In one embodiment, one or more of the fork shock assembly, the rear shock assembly 38, the seat post 33, the handlebars 36, etc. includes one or more active damping components (e.g., a movable valve). In one embodiment, vehicle 50 includes one or more sensors, smart components, etc. In one embodiment, a sensor 5 is positioned near the rear axle 15 of the vehicle 50. In another embodiment, a sensor 35 is positioned near the front fork 34. In yet another embodiment, both the sensor 5 and the sensor 35 are on the vehicle 50. Generally, one or more sensors (such as sensor 5 and / or sensor 35) and / or smart components are used to identify and / or monitor characteristics (or changes in characteristics) such as terrain, environment, temperature, vehicle speed, vehicle pitch, vehicle roll, vehicle yaw, component activity, etc. It should be understood that one or more sensors can be embedded, moved, installed, etc. in any suitable configuration and allow any suitable range of adjustment as needed. Although multiple sensors are shown in FIG. 1A, it should be understood that there can be only a single sensor or more than two sensors in operation. Typically, the sensor can be any suitable force or acceleration transducer (e.g., strain gauge, Wheatstone bridge, accelerometer, hydraulic sensor, interferometer-based sensor, optical sensor, thermal sensor, or any suitable combination thereof). The sensor can utilize solid-state electronic devices, electromechanical principles, or Micro Electro Mechanical Systems (MEMS) or any other suitable mechanism. In one embodiment, the sensor includes a uniaxial self-powered accelerometer, such as an ENDEVCO® model 2229C for example. In one embodiment, one or more of the sensors are a uniaxial accelerometer, a triaxial accelerometer, a measurement-type sensor such as an infrared-based time-of-flight sensor, radar, 2D and 3D imagers, ultrasonic sensors, photoelectric sensors, lidar, etc. In one embodiment, the measurement-type sensor is a STMicroelectronics sensor, and particularly a STMicroelectronics sensor of model VL53L0X. In one embodiment, the angular orientation of one or more sensors can move within a given range, thereby allowing the force components sensed by the sensors to change relative to the force (vector) input. In one embodiment, the value of this range is approximately 120°. In one embodiment, the value of this range is approximately 100°. It should be understood that the sensors can move or be mounted in any suitable configuration and allow any suitable range of adjustment as needed. This is useful for adjusting the sensitivity of the sensors to various expected terrains as well as bicycle speed conditions. For example, for terrain differences or "bounces / slants" of a constant magnitude, the bicycle speed affects the vector magnitude of the force input to the bicycle wheels. For a constant bicycle speed, different magnitudes of bounces and slants also affect the vector input angle of the wheels. One or more sensors can be directly attached to the swing arm 26, any link of the swing arm 26, an intermediate mounting member, the front fork 34, or any other part or parts of the vehicle 50 as may be useful. In one embodiment, the sensor is fixed to the unsprung part of the vehicle 50, such as the swing arm assembly 26 for example. In one embodiment, the sensor is fixed to the sprung part of the vehicle 50, such as the frame 24. Typically, one or more sensors can be combined with other vehicle structures, suspension components, suspension component controllers, and data processing systems, etc., as disclosed in U.S. Patent 10,036,443, the entire content of which is incorporated herein by reference. In one embodiment, sensor data is provided to controller 39. In one embodiment, controller 39 uses the sensor data to adjust the frequency-tunable TMD 100. In one embodiment, controller 39 adjusts the frequency-tunable TMD 100 by signaling to modify one or more of the spring stiffness, mass, and / or damper characteristics of the frequency-tunable TMD 100 as described herein. In one embodiment, the sensor data is provided to the frequency-tunable TMD 100 rather than to a separate controller 39 component, and the frequency-tunable TMD 100 will include a controller similar to controller 39. In one embodiment, controller 39 uses the sensor data to perform suspension adjustments. In one embodiment, suspension controller 39 performs suspension adjustments on one or more of the shock absorber assemblies of vehicle 50 having active damping components (such as active valves). As an example, see the electronic valve of U.S. Patent 9,353,818, which is incorporated herein by reference in its entirety, as another example of a different type of "electronic", "active", or "main active" valve. Figure 1B is a perspective view of a TMD system 75 on vehicle 50 according to an embodiment. Generally, the TMD system 75 includes one or more TMDs 100. It should be understood that one or more TMDs 100 can be embedded, moved, installed, etc. in any suitable configuration and allow any suitable range of adjustments as may be needed. Although multiple TMD 100 positions are shown in Figure 1B, it should be understood that there may be only one frequency-tunable TMD 100 or more than one frequency-tunable TMD 100 operating with non-frequency-tunable TMDs or some non-frequency-tunable TMDs. Additionally, although several TMD 100 positions are shown, the embodiments are fully suitable for fewer TMD 100 positions, more TMD 100 positions, and / or different TMD 100 positions as discussed herein. Referring now to FIGS. 1A and 1B, in one embodiment, the TMD 100 is an independent unit that can be mounted or coupled to one or more vehicle components (e.g., externally, internally, and / or integrally). Similarly, although several TMD 100 positions are shown, the embodiment is well-suited for fewer TMD 100 positions, more TMD 100 positions, and / or different TMD 100 positions. For example, there may be TMD 100 positioned near and / or coupled to one, more, or each of the handlebar 36, the steering tube of the fork assembly 34, the fork assembly 34, the fork lower, the brake caliper, the front axle, and / or the rear axle, and the fork arch, the fork crown, the rear shock assembly, the bottom bracket, etc. through the head tube of the frame 24, the seat tube of the frame 24, the seat post 33, the chain stay portion of the swing arm 26, the seat support portion of the swing arm 26, etc. The frequency-tunable TMD 100 can be mounted towards the front or rear of the vehicle 50 to reduce the tremors of bicycles such as, but not limited to, full-suspension mountain bikes (MTB), hardtail bikes, gravel bikes, road or city bikes, electric bikes, etc. In one embodiment, at least one TMD is coupled to the unsprung mass of the vehicle. In one embodiment, at least one TMD is coupled to the sprung mass of the vehicle. In one embodiment, the TMD system 75 uses multiple TMDs. For example, at least one frequency-tunable TMD 100 and at least one TMD are coupled to some or each of the handlebar 36, the steering tube of the fork assembly 34 through the head tube of the frame 24, the seat tube of the frame 24, the seat post 33, the chain stay portion of the swing arm 26, the seat support portion of the swing arm 26, the fork assembly, the rear shock assembly, the bottom bracket, etc. In one embodiment, multiple frequency-tunable TMD 100s are coupled to two or more components such as the handlebar 36, the steering tube of the fork assembly 34 through the head tube of the frame 24, the seat tube of the frame 24, the seat post 33, the chain stay portion of the swing arm 26, the seat support portion of the swing arm 26, the fork assembly, the rear shock assembly, the bottom bracket, etc. In one embodiment, the shape of the frequency-tunable TMD 100 is optimized to fit its mounting area (e.g., handlebar, steering tube, fork assembly, fork lower, fork crown, near the axle, rear shock assembly, external, inside the frame, or outside the frame, etc.), while maintaining its ability to operate within the desired frequency range. Referring now to FIG. 2A, a schematic diagram of a vehicle 50 according to an embodiment is shown. The vehicle 50 travels along the terrain in the direction 93. When the vehicle 50 moves, it will generate a certain amount of vibration energy. In other words, when the vehicle moves on the terrain and encounters an event 105, the system will be excited, and due to the vibration energy generated by the introduced operation, the system will start to oscillate. Vehicle designers and manufacturers strive to ensure that many components and the vehicle as a whole will contribute to dissipating vibrational energy. For example, components such as handlebars, forks, frames, swingarms, etc. are designed to strike a balance between rigidity and flexibility. detrimentally, if the components are too rigid, they will not absorb any energy. Instead, when the component encounters events 105 such as rocks, bumps, landings, curbs, gravel, chunks, rolls, tilts, hills, etc., it will allow that energy to pass directly through the system and be transmitted to the operator. In addition to providing a vibrating ride to the operator, this will also cause traction and control problems for the vehicle 50 due to wheel bounce, wheel slip, tremors, non-contact torques between the wheel and the ground, etc. Furthermore, without a certain amount of flexure, when encountering a large event 105 (or repeatedly encountering event 105), one or more components of the vehicle 50 will break, stress fracture, crack, etc. To address this issue, a certain amount of flexure (or damping feature components such as spring 102 and mass 101) is built into the vehicle 50 and component designs to allow some event energy to be damped or dissipated, thereby allowing the vehicle 50 to traverse similar terrains and events 105 without causing breakage, stress fracture, crack, etc. Depending on the terrain and / or event 105 to be encountered, these damping feature components may also include components such as shock absorbers, rubber mounts, pneumatic tires, springs, etc., which are incorporated into the vehicle design and are used to further damp, absorb, and / or dissipate the energy introduced by the movement of the vehicle and any event encounters. However, any one of these components and possibly the entire vehicle vibrates freely and will therefore have one or more natural frequencies. For example, in FIG. 3A, a graph 300 of the amplitude versus frequency of a front fork assembly 34 according to an embodiment is shown. To obtain data, the front fork assembly 34 is subjected to a change in frequency. Curve 305 is the acceleration curve without any additional damping. Curve 301 is the acceleration curve with a TMD added that oscillates in the front-to-back direction. As can be clearly seen from graph 300, the natural frequency of the front fork assembly 34 is between 22 Hz and 26 Hz and is centered at 24 Hz. Thus, when the forced vibration reaches the natural frequency, resonance occurs, resulting in a large amplitude spike in the undamped component as shown by curve 305. However, by utilizing a TMD (tuned between 22 Hz and 26 Hz) and installing it to the lower part of the fork (such as the unsprung mass), the amplitude of the resonance peak is significantly reduced, and the peak actually appears at a lower frequency. In FIG. 3B, a graph 350 of the position versus time of the x-axis position of the front fork assembly 34 during forced vibration according to an embodiment is shown. Curve 355 shows the x-axis position of the fork without a TMD. Curve 351 shows the x-axis position of the fork with a TMD added that oscillates in the front-to-back direction. Referring now to FIG. 2B, a schematic diagram of a frequency-tunable TMD 100 added to a vehicle 50 according to an embodiment is shown. Generally, the frequency-tunable TMD 100 is tuned by adjusting the mass, spring, or damping. In one embodiment, the frequency-tunable TMD 100 will include adjustable features such as an additional mass and an adjustable damping ratio and / or spring stiffness that is electronically and / or manually adjustable by a user, such as a knob control. In one embodiment, the frequency-tunable TMD 100 is initially adjusted to match the natural frequency of the vehicle (or a component of the vehicle), and any change in frequency is made during operation to match (and thus damp) the vibrational energy caused by the operation at the current actual (or near actual) time. Referring now to FIG. 2B and FIGS. 3A - 3B, based on the data of the graph 300 and the graph 350, it is clear that with the frequency-tunable TMD 100 tuned between 22 Hz and 26 Hz, oscillating in the fore-aft direction and mounted to the lower fork, the oscillation of the fore-aft position (e.g., the x-axis) decreases along with the amplitude of the resonance peak 300. However, it should be understood that although a favorable combination of mass, spring, and damper can be employed to reduce the target mode, an incorrect combination of mass, spring, and damper may have an adverse effect, including making the oscillation worse. FIG. 4A is a table 400 showing equations for determining the appropriate mass, damping coefficient, and spring stiffness of a TMD for acting on a given object (e.g., the mass 1 in FIG. 2B or the vehicle 50) according to an embodiment. FIG. 4B is a table 425 for additional calculations of the TMD according to an embodiment. The result is a formula for adjusting the frequency-tunable TMD 100. Where f(t) is the input force, M is the mass, C is the damping coefficient, and K is the spring stiffness. Therefore, for a given input force, the acceleration (which causes vibration) can be reduced by adjusting one, some, or each of the damping, spring stiffness, and / or mass of the frequency-tunable TMD 100. In other words, the TMD exists in its basic form as a spring, a mass, and a damper. The spring can be a cantilever spring, a helical spring, an extension spring, a compression spring, an air spring, etc. The mass can be any desired or undesired mass such as self-weight, a stack of magnets, an existing internal mass, etc. The damper can be any damping mechanism (electromagnetic damping, viscous damping, etc.). Thus, the TMD is not a single specific mass, or a specific spring stiffness, or a specific damper, but rather a combination of a specific spring, a specific damper, and a specific mass that allows a selected vibration mode to be targeted and eliminated. As discussed herein, the problem with existing TMDs is that they cannot provide multi-mode and / or active frequency tunability. That is, while it is possible to construct a power spectral density (PSD) curve of the collected acceleration data to better understand the unwanted vibration modes on a vehicle or its components (such as those shown in Figure 3A). The PSD curve will not include the immediate unwanted vibration modes that actually occur on a particular road due to a particular event 105, particular terrain, particular vehicle configuration and component combination, particular rider style, etc. The immediate unwanted vibration modes result in poor vehicle traction, muscle fatigue, limited rider confidence, discomfort, etc. For example, when using a frequency-tunable TMD 100 in the handlebar 36, front fork 34, etc. This structure will have some known oscillation resonance frequencies. For example, the fork assembly has a known length and known mass at its ends. Therefore, the oscillation of the fork assembly during normal operation will be known, and the frequency-tunable TMD 100 can be pre-tuned to damp those expected oscillations. However, there will also be oscillations caused by the terrain being traversed. For example, off-road bumps, cobblestone sections, etc. These terrain features (or event 105) will introduce immediate unwanted vibration modes that are different from the expected frequency oscillations but can also be addressed by the frequency-tunable TMD 100. Generally, the location of negatively perceived vibrations can exist in or penetrate through any medium of the vehicle 50, so the frequency-tunable TMD 100 can be located on the sprung mass or unsprung mass of the vehicle 50. Examples of unsprung mounting locations include brake mounting bosses, front or rear axles, lower legs of the front fork, etc. Examples of sprung mounting locations include frame mounting holes, bottom brackets, handlebars, etc. For example, the frequency-tunable TMD 100 can be used to reduce and / or eliminate vibrations such as those from cobblestone streets, gravel, etc. In one embodiment, by reducing and / or eliminating terrain-induced vibrations, vehicle performance problems such as wheel bounce, wheel slip, chatter, etc. will be reduced; this will result in better grip, traction, handling, etc. for the vehicle. In a hardtail bicycle, the frequency-tunable TMD 100 will help reduce and / or eliminate vibrations in the rear without a suspension. In a suspension section (such as a front suspension vehicle or a full suspension vehicle), the frequency-tunable TMD 100 (such as working with a shock absorber assembly) will also help reduce and / or eliminate residual vibrations. It should also be understood that there may be multiple frequency - adjustable TMDs installed at different positions, and one or both of user - specific (e.g., handlebar, seat, frame, pedal, etc.) vibration and resonance characteristic adjustments and vehicle - specific (e.g., grip, wheel bounce, wheel slip, tremor, traction, handling, etc.) vibration and resonance characteristic adjustments are performed. Accordingly, the frequency - adjustable TMD 100 solves problems such as imperfect tire grip on the ground, perception of tremors, loss of comfort on fast - repeating bumps, etc. By utilizing the tuned mass damper system 75, vehicle handling is improved by increasing the time the wheels spend on the ground, increasing the operator's confidence and comfort, and reducing tremors, bounce, vibration, traction loss, etc. In one embodiment, the frequency - adjustable TMD 100 is adjusted via semi - active changes to the spring stiffness, mass, and / or damping of the frequency - adjustable TMD 100 shown in FIGS. 5A - 7B, via semi - active components within the frequency - adjustable TMD 100 shown in FIGS. 8A - 8B, via the frequency - adjustable TMD 100 for power generation shown in FIGS. 9A - 9B, via a multimodal TMD group operating in a combined manner shown in FIGS. 10A - 10C, and / or via a combination of two or more of the embodiments in FIGS. 5A - 10C. In one embodiment, a control system (similar to the controller 39 in FIGS. 1A - 1B) is used to monitor the movement of the mass body 101 within the frequency - adjustable TMD 100 to ensure that the amplitude of oscillation does not become greater than the operating range of the frequency - adjustable TMD 100. For example, the damping of the mass body 101 in the frequency - adjustable TMD 100 can be modified by changing the resistance of the coil, magnetorheological fluid, ports on the mass body 101, etc. Generally, the resistance can be set to be optimal for the charging circuit, damping characteristics, etc. In one embodiment, a magnet is used to generate a magnetic flux, and when the magnet is pushed through the magnetic flux, the coil generates resistance. By adjusting the resistance generated by the coil, the movement of the magnet through the magnetic flux is also adjusted. This resistance adjustment will allow the resistance of the frequency - adjustable TMD 100 to increase to slow down the movement of the magnet through the magnetic flux, thereby ensuring that the mass body does not strike the ends of the frequency - adjustable TMD 100 during large - amplitude events (e.g., jumping, landing, edge impact, etc.). Now referring to FIG. 5A, a front view of the handlebar 36 according to an embodiment is shown. FIG. 5B is a cross - sectional view of the frequency - adjustable TMD 100 optimized to be fitted within the handlebar 36 according to an embodiment. Referring now to FIGS. 5A and 5B, in one embodiment, the frequency adjustable TMD 100 mounted to the handlebar is mounted using an external section of the handlebar 36 or an independent box mounted therein. In one embodiment, the frequency adjustable TMD 100 mounted to the handlebar includes a cylindrical housing 505 to accommodate a rod-shaped mass 101 coupled to the housing 505 via a spring 102. The oscillation of the mass 101 is damped by the spring 102 and by a fluid 515 within the housing 505. In one embodiment, the fluid 515 is a smart fluid having adjustable properties such as adjustable viscosity, surface tension, yield stress, etc., such that the damping characteristics of the fluid 515 can be modified. In one embodiment, the fluid 515 is a Magnetorheological (MR) fluid and the property changes are adjusted and / or controlled by the application of a magnetic field. In one embodiment, the fluid 515 is an Electrorheological (ER) fluid and the property changes are adjusted and / or controlled by the application of an electric field. Accordingly, the frequency of the frequency adjustable TMD 100 is modified during operation by changing the damping characteristics of the fluid 515. In one embodiment, the modification is controlled by one or more components of the frequency adjustable TMD system 75 as described in FIG. 1B. Referring now to FIG. 6A, a front cross-sectional view of a frequency adjustable TMD 100 having a semi-active variable spring stiffness and a small volume 620 configuration according to an embodiment is shown. In FIG. 6B, a front cross-sectional view of a frequency adjustable TMD 100 having a semi-active variable spring stiffness and a medium volume 650 configuration according to an embodiment is shown. In FIG. 6C, a front cross-sectional view of a frequency adjustable TMD 100 having a semi-active variable spring stiffness and a large volume 675 configuration according to an embodiment is shown. Referring now to FIGS. 6A-6C, the frequency adjustable TMD 100 includes a mass 101 suspended between two air springs 102 within a chamber 605. However, the volume of the chamber 605 is changed by expanding or contracting an end 612. By adjusting the volume of the chamber 605, the spring stiffness (K) of the air spring 102 will be adjusted, which will similarly adjust the damping frequency of the frequency adjustable TMD 100. In one embodiment, adjusting the volume of the chamber 605 by expanding or contracting the end 612 is performed in a semi-active manner. For example, a motor is used to extend or retract the end 612 to change the volume of the air chamber during operation and thus change the spring stiffness. In one embodiment, the frequency - adjustable TMD 100 is an independent box and is positioned or located within (these components) using the steering tube of the front fork 34, the legs of the front fork 34, the frame 24, the handlebar 36, the head tube of the frame 24, the seat tube of the frame 24, the seat post 33, the chain - support portion of the swing arm 26, the seat - support portion of the swing arm 26, etc. In one embodiment, the mass body 101 is optimized for a given frequency range and will move vertically as the bicycle moves. The mass body 101 will return to its initial position via a spring and its movement will be slowed down by damping. In one embodiment, the damping is the result of restricting the air movement around the mass body 101 to slow down the movement of the mass body 101. This damped movement of the mass body 101 will help to eliminate tremors during a rapid collision, thus improving the rider's contact with the ground. In addition, this damped movement of the mass body 101 will increase comfort by reducing the vibrations transmitted to the rider. In one embodiment, the adjustable range of the frequency - adjustable TMD 100 can be changed by changing the mass body 101, using different gases within the air damper 102, or a combination thereof. Now referring to FIG. 7A, a front - view cross - sectional view of a frequency - adjustable TMD 100 with a spring stiffness changed via a manually - varied pressure configuration according to an embodiment is shown. The frequency - adjustable TMD 100 includes a mass body 101 suspended between two air springs 102 within a chamber 705. In addition, at least one valve 710 (such as a Schrader valve, etc.) provides the manual ability to change the pressure of the air springs 102 within the chamber 705. By changing the pressure within the chamber 705, the spring stiffness (K) of the air springs 102 is adjusted, which will similarly adjust the damping frequency of the frequency - adjustable TMD 100. Now referring to FIG. 7B, a front - view cross - sectional view of a frequency - adjustable TMD 100 with a semi - actively - varied spring stiffness via a semi - active pressure - change configuration according to an embodiment is shown. Similar to FIG. 7A, the frequency - adjustable TMD 100 includes a mass body 101 suspended between two air springs 102 within a chamber 705. However, instead of (or in addition to) the at least one valve 710 of FIG. 7A, a compressor 730 is coupled to the chamber 705 to provide the semi - active (or automatic) ability to change the pressure of the air springs 102 within the chamber 705. By semi - actively changing the pressure within the chamber 705, the spring stiffness (K) of the air springs 102 is adjusted, which will similarly adjust the damping frequency of the frequency - adjustable TMD 100. In one embodiment, the chamber 705 further includes one or more exhaust valves 735. In one embodiment, there are no exhaust valves 735 because the valves used by the compressor 730 are also used to release air pressure. In one embodiment, the compressor 730 is an in-vehicle air compressor system and acts vertically into the air damper 102 of the frequency-adjustable TMD 100 to allow the pressure in the air chamber 705 to be adjusted during operation via the in-vehicle air compressor system controller. In one embodiment, the frequency-adjustable TMD 100 of FIGS. 7A and 7B is similarly adjustable, operable, and located in one or more of the positions disclosed in the discussion of the frequency-adjustable TMD 100 of FIGS. 6A-6C. In one embodiment, the frequency-adjustable TMD 100 may include a combination of the volume change feature of FIGS. 6A-6C and the pressure change feature of FIGS. 7A-7B to adjust the spring stiffness of the air spring 102. In one embodiment, one or both of the volume change feature and / or the pressure change feature are performed semi-actively. Referring now to FIG. 8A, a front cross-sectional view of a frequency-adjustable TMD 100 with a semi-active control damping coefficient according to an embodiment is shown. In FIG. 8B, a cross-sectional view of section A-A of FIG. 8A according to an embodiment is shown. Referring now to FIGS. 8A-8B, in one embodiment, the frequency-adjustable TMD 100 is an independent chamber 805 that is positioned or located within (these components) using the steering tube of the front fork 34, the legs of the front fork 34, the frame 24, the handlebar 36, the head tube of the frame 24, the seat tube of the frame 24, the seat post 33, the chain stay portion of the swing arm 26, the seat support portion of the swing arm 26, etc. In one embodiment, the mass body 101 is optimized for a given frequency range and will move vertically as the bicycle moves. The mass body 101 will return to its initial position via the spring 102, and its movement will be slowed down by damping. In one embodiment, damping is the result of restricting the movement of the fluid 815 (such as oil, air, smart fluid, etc.) around the mass body 101 to slow down the movement of the mass body 101. In one embodiment, as shown in FIG. 8B, the mass body 101 includes a flow path 823 having an active valve 825. By providing a flow path 823 controlled by a semi-active or automatically adjustable active valve 825, the restriction of the movement of the oil or air around the mass body 101 within the chamber 805 can be adjusted. In doing so, an adjustable damping coefficient (C) is used to modify the damping frequency of the frequency-adjustable TMD 100. In one embodiment, the adjustable range of the frequency-adjustable TMD 100 is changed by changing the mass body 101, using different gases within the air damper 102, or a combination thereof. Referring now to FIG. 9A, a perspective view of a frequency - adjustable TMD 100 with a semi - active control damping coefficient according to an embodiment is shown. In FIG. 9B, a cross - sectional view of the frequency - adjustable TMD 100 with the semi - active control damping coefficient of FIG. 9A according to an embodiment is shown. Referring now to FIGS. 9A - 9B, in one embodiment, the frequency - adjustable TMD 100 is an independent chamber 905. The independent chamber 905 is positioned or located (within these components) by using the steering tube of the front fork 34, the legs of the front fork 34, the frame 24, the handlebar 36, the head tube of the frame 24, the seat tube of the frame 24, the seat post 33, the chain - support portion of the swing arm 26, the seat - support portion of the swing arm 26, etc. In one embodiment, the frequency - adjustable TMD 100 employs a linear compression spring 102. The mass body 101 is those movers typically characterized for use in electromagnetic generators and includes a sliding surface 933 and a specially - oriented magnet stack 934. In one embodiment, the electromagnetic generator is linear. In another embodiment, the electromagnetic generator is rotary. The damper is electromagnetic and is controlled via an external resistor and coil geometry in one embodiment. In one embodiment, the spring is a compression spring, a tension spring, an air spring, etc. In one embodiment, the mass body 101 is optimized for a given frequency range and will move vertically as the bicycle moves. The mass body 101 will return to its initial position via the spring 102, and its movement will be slowed by electromagnetic damping. Although in one embodiment, the mass body moves vertically as the bicycle moves, in another embodiment, the mass body can be oriented in any direction. In one embodiment, the orientation depends on the resonance mode. In one embodiment, an adjustable damping coefficient (C) is used to modify the damping frequency of the frequency - adjustable TMD 100. In one embodiment, the frequency - adjustable TMD 100 will also generate electricity. Thus, in addition to providing damping, the movement of the mass body 101 will also allow energy to be harvested from the movement of the mass body 101 and the damping. In one embodiment, the energy harvested by the frequency - adjustable TMD 100 is provided to a wireless shock absorber to supply power to the shock absorber communication system and / or the active valve system. In one embodiment, the energy is provided to the controller 39 to power the communication system, the processor, etc. of the controller. In one embodiment, the energy is provided to one or more sensors, batteries, headlight / tail - light, compressor 730, charging port, and / or one or a combination of power - consuming components and / or storage components. Referring now to FIG. 10A, a schematic diagram of a multimodal TMD system 1000 according to an embodiment is shown. Generally, the multimodal TMD system 1000 utilizes two or more shock damping components 1010 coupled to multiple TMDs. In one embodiment, one, some, or all of the TMDs are frequency-tunable TMDs 100. In one embodiment, one, some, or all of the frequency-tunable TMDs 100 are power-generating, as shown in FIGS. 9A and 9B. In one embodiment, the spring portion of the frequency-tunable TMD 100 coupled to the shock damping component 1010 will serve as a reservoir and will thus contain hydraulic fluid. For example, two upper frequency-tunable TMDs will serve as upper reservoirs (e.g., for compression stroke), and two lower frequency-tunable TMDs will serve as lower reservoirs (e.g., for rebound stroke). Conversely, the spring portion of each frequency-tunable TMD 100 coupled to another frequency-tunable TMD 100 will include a gas such as air, nitrogen, etc. In one embodiment, one, some, or all of the connectors between each frequency-tunable TMD 100 will include valves for engaging / disengaging. In one embodiment, one or more of the valves will be active valves. By coupling the system to one or more valves, the multimodal TMD system 1000 will be able to engage (e.g., cross-link) for road control and be able to disengage for off-road operation. By using active valves, the engagement and disengagement will be controllable by a controller, an in-vehicle infotainment (IVI) system, etc. In one embodiment, the engagement / disengagement will be automatic, as determined by the controller. In one embodiment, the engagement / disengagement will be performed by the controller after an operator inputs a command. In one embodiment, the multimodal TMD system 1000 will include a compressor, such as compressor 730 of FIG. 7B, to control roll, change the ride height of the shock damping component, modify the frequency of the frequency-tunable TMD 100, etc. In one embodiment, one, some, or all of the connectors between each frequency-tunable TMD 100 and the shock damping component 1010 will include valves. In one embodiment, one or more of the valves will be active valves. By coupling the system to one or more valves, the multimodal TMD system 1000 will be able to provide roll control combined with damping. Referring now to FIG. 10B, a schematic diagram of a multimodal TMD system 1000 according to an embodiment is shown. Generally, the multimodal TMD system 1000 utilizes two or more damping components 1010 (such as airbags, etc.) that act as springs, and the mass body 101 is located between the damping components 1010. Generally, the operation of the multimodal TMD system 1000 is similar to the operation disclosed in the discussion of FIGS. 6A-9B, the entire content of which is incorporated herein by reference and will not be repeated for clarity. Referring now to FIG. 10C, a schematic diagram of a multimodal TMD system 1000 according to an embodiment is shown. Generally, the multimodal TMD system 1000 includes a chamber 1065 that includes spring 102 portions (such as mechanical, gas, or a combination thereof) located at its top and bottom and a mass body 101. In one embodiment, the mass body 101 includes an intermediate section filled with a fluid 1016 (such as oil, etc.), and an optional fixed passive damping or semi-active damping component 1015 located within the intermediate section. In one embodiment, the fluid 1015 (constituting the mass body 101) is separated from the spring 102 portions by an Internal Floating Piston (IFP) 1020. In one embodiment, the spring 102 portions are coupled to an additional volume container (such as evol 1050). In one embodiment, two different spring 102 portions can be tuned to target two different frequencies. For example, in one embodiment, the multimodal TMD system 1000 can isolate the off-road wheel hop frequency (such as, for example, 10 Hz). In one embodiment, in a situation where a greater amplitude is required for the multimodal TMD system 1000, the valve 1070 is opened to reduce the effective K (similar to changing the volume as discussed herein with reference to FIGS. 6A-6C), and thereby reduce the off-road frequency of the multimodal TMD system 1000. In one embodiment, the multimodal TMD system 1000 will also isolate the road surface roughness frequency (such as, for example, 30 Hz) on the road. In one embodiment, in a situation where a lower amplitude is required for the multimodal TMD system 1000, the valve 1070 is closed to increase the effective K (similar to changing the volume as discussed herein with reference to FIGS. 6A-6C), and thereby increase the road frequency of the multimodal TMD system 1000. Generally, in a typical TMD, the mass body 101 must be large enough to work effectively with the damper to dissipate energy. However, in some vehicle situations, such as road bicycles, high-performance vehicles, etc., weight is a critical factor. Therefore, the addition of any additional mass must be carefully considered. However, by utilizing the damping fluid that is typically present within the damper used for the TMD as an important part of the mass body 101, the TMD system 1000 will provide a damping function with a minimal amount of weight added to the vehicle. In one embodiment, the mass body 101 of the multimodal TMD system 1000 will include a fluid path and an active valve control to modify the amount of fluid 1016 within the mass body 101, thereby modifying the mass body to change the damping frequency of the multimodal TMD system 1000. In one embodiment, the multimodal TMD system 1000 is installed to the shock absorber body that serves as a reservoir. In one embodiment, if the multimodal TMD system 1000 is installed to the shock absorber strut, it will target damped vibrations. Conversely, if the multimodal TMD system 1000 is installed to the shock absorber in a reverse configuration, it will target undamped vibrations. Thus, during riding, the terrain can include repeatable events 105 such as rocks, turf, and dirt, uneven road surfaces, bumps, jolts, etc., which will introduce new and unwanted frequencies to the vehicle 50, and these new and unwanted frequencies will be addressed by the frequency-adjustable TMD 100. However, in one embodiment, the frequency-adjustable TMD 100 will also be able to adjust the damping frequency due to other events such as but not limited to the user changing their grip, standing on the pedals, lowering the dropper seat post, etc. For example, a rider can change their style based on different terrains, speeds, gravity, acceleration, climbing, full-speed sprinting, etc. Although changes in riding style may introduce new and / or different oscillations and / or vibrations and / or amplitudes, in one embodiment, by utilizing sensor information to identify short-term changes in riding style, the frequency-adjustable TMD 100 will not change within a predefined or user-defined time period, or will change to address and reduce rider-induced pedal wobbling, bouncing, wheel spin, etc. In one embodiment, after the sensor determines that the rider has returned to the normal riding position, the frequency-adjustable TMD 100 will then change from controlling rider-induced vibrations and return to handling vibrations and oscillations caused by the terrain and / or events 105. In one embodiment, the frequency - adjustable TMD 100 is tuned such that the damped vibration frequency and / or the resonance frequency is synchronized with the expectations of the intended user. Similarly, the frequency - adjustable TMD 100 can be tuned such that the damping frequency range includes a smaller window that better correlates with the vibration frequency and / or resonance frequency of an individual user, the rider style, etc., to obtain better feedback / feel, etc. In one embodiment, the fine - tuning can occur during one or more rides, can be stored in memory, and can be different for different terrains, temperatures, performances, etc. For example, the user can establish different damping frequency ranges for roads, gravel, sand, dirt, etc. These different damping frequency ranges can be stored in the controller 39, the user's mobile device, the memory of the frequency - adjustable TMD 100, etc. When the user wants to ride, they will select the appropriate tuning for the given situation. Additionally, if the ride changes, such as from a dirt road to a paved road, from cold to warm, from high speed to moderate, etc., the user can manually select (or the frequency - adjustable TMD system 75 can automatically initiate) different frequency - damping tunings based on the changed parameters. As a result, the frequency - adjustable TMD 100 is capable of automatically (and / or in accordance with the user's input) changing the felt vibration, the damping frequency range, etc. The examples set forth herein are for the purpose of best explaining, describing a particular application, and thereby enabling one of ordinary skill in the art to make and use an embodiment of the described examples. However, one of ordinary skill in the art will recognize that the foregoing description and examples are presented for purposes of illustration and example only. The described description is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Rather, the specific features and acts described above are disclosed as example forms for implementing the claims. References throughout the document to "one embodiment", "certain embodiments", "an embodiment", "various embodiments", "some embodiments", etc. mean that the particular features, structures, or characteristics described in connection with that embodiment are included in at least one embodiment. Thus, such phrases appearing in different places throughout the specification can refer to the same embodiment, different embodiments, combinations of embodiments, etc. In addition, in some embodiments, the specific features, structures, or characteristics of an embodiment are not combined with one or more other features, structures, or characteristics of one or more other embodiments. In another embodiment, the specific features, structures, or characteristics of some embodiments may be combined with one or more other features, structures, or characteristics of one or more other embodiments in any suitable manner. In yet another embodiment, the specific features, structures, or characteristics of any embodiment may be combined with one or more other features, structures, or characteristics of one or more other embodiments in any suitable manner without limitation. 100: Tuned mass damper (TMD) 50: Vehicle 75: Tuned mass damper (TMD) system

Claims

1. A tuned mass damper, comprising: mass body; At least one spring is connected to the mass body, and the at least one spring has spring stiffness; A damper that dampens the motion of the mass, the damper including a damping coefficient, wherein at least one of the spring stiffness and the damping coefficient is adjustable during vehicle operation to modify the frequency damped by the tuned mass damper. And an active component connected to the tuned mass damper, the active component being configured to electronically adjust at least one of the spring stiffness and the damping coefficient.

2. The tuned mass damper as described in claim 1, wherein, Both the spring stiffness and the damping coefficient are adjustable during vehicle operation to modify the frequency damped by the tuned mass damper.

3. The tuned mass damper as described in claim 1, further comprising: A controller that is communicatively connected to sensors attached to the vehicle and configured to receive sensor information and determine the frequency of the modification.

4. The tuned mass damper as claimed in claim 1, wherein, The at least one spring is an air spring.

5. The tuned mass damper as described in claim 4, wherein, The spring stiffness of the air spring is adjusted by changing the volume of the air spring.

6. The tuned mass damper as described in claim 4, wherein, The spring stiffness of the air spring is adjusted by changing the pressure of the gas in the air spring.

7. The tuned mass damper as claimed in claim 1, wherein, The damper is a fluid.

8. The tuned mass damper as described in claim 7, wherein, The damping coefficient of the fluid is adjusted by modifying the flow rate through the flow port in the mass body, the flow rate being controlled by an active valve.

9. The tuned mass damper as claimed in claim 1, wherein, The damper is a smart fluid having at least one adjustable characteristic to change the damping coefficient.

10. The tuned mass damper as claimed in claim 9, wherein, The smart fluid is selected from the group consisting of magnetorheological (MR) fluids and electrorheological (ER) fluids.

11. The tuned mass damper as claimed in claim 1, wherein, The tuned mass damper is connected to the vehicle at a location selected from groups including external, internal, and integrated.

12. The tuned mass damper as claimed in claim 1, wherein, The tuned mass damper is connected to the damping assembly, and the tuned mass damper is configured to function as a fluid reservoir and the tuned mass damper.

13. The tuned mass damper as claimed in claim 1, wherein, The mass includes: a sliding surface; and a deliberately oriented stack of magnets; and the damper is electromagnetic, such that the tuned mass damper is configured to provide tuned damping and harvest energy using the motion of the mass.

14. The tuned mass damper as claimed in claim 13, wherein, The collected energy is supplied to components other than the tuned mass damper.

15. A tuned mass damper, comprising: A mass body, wherein at least a portion of the mass body is a damping fluid to dampen the motion of the mass body, the damping fluid having a damping coefficient, and at least one spring connected to the mass body, the at least one spring having a spring stiffness.

16. The tuned mass damper as claimed in claim 15, wherein, At least one of the spring stiffness and the damping coefficient is adjustable during vehicle operation to modify the frequency damped by the tuned mass damper.

17. The tuned mass damper as claimed in claim 15, wherein, The damping fluid uses a shared self-damping component.

18. The tuned mass damper as claimed in claim 15, wherein, The tuned mass damper includes at least one semi-active valve.

19. A tuned mass damper, comprising: A mass body, the mass body comprising: a sliding surface; and a deliberately oriented stack of magnets; at least one spring connected to the mass body, the at least one spring having a spring stiffness; an electromagnetic damper for damping the motion of the mass body, the electromagnetic damper including a damping coefficient, wherein at least one of the spring stiffness and the damping coefficient is adjustable during vehicle operation to modify the frequency damped by the tuned mass damper, and wherein the tuned mass damper is configured to harvest energy using the motion of the mass body; and an active component connected to the tuned mass damper, the active component being configured to electronically adjust at least one of the spring stiffness and the damping coefficient.

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