Design Approach for Reducing Cross-Axis Sensitivity in a Single-Drive Multi-Axis MEMS Gyroscope

In this paper, a new design technique is presented to estimate and reduce the cross-axis sensitivity (CAS) in a single-drive multi-axis microelectromechanical systems (MEMS) gyroscope. A simplified single-drive multi-axis MEMS gyroscope, based on a mode-split approach, was analyzed for cross-axis sensitivity using COMSOL Multiphysics. A design technique named the “ratio-matching method” of drive displacement amplitudes and sense frequency differences ratios was proposed to reduce the cross-axis sensitivity. Initially, the cross-axis sensitivities in the designed gyroscope for x and y-axis were calculated to be 0.482% and 0.120%, respectively, having an average CAS of 0.301%. Using the proposed ratio-matching method and design technique, the individual cross-axis sensitivities in the designed gyroscope for x and y-axis were reduced to 0.018% and 0.073%, respectively. While the average CAS was reduced to 0.045%, showing a reduction rate of 85.1%. Moreover, the proposed ratio-matching method for cross-axis sensitivity reduction was successfully validated through simulations by varying the coupling spring position and sense frequency difference variation analyses. Furthermore, the proposed methodology was verified experimentally using fabricated single-drive multi-axis gyroscope.

The intensification of the outer suburbs and the impact on travel behaviour: an analysis of York Region

In an effort to retrofit outer suburban municipalities to be more supportive of public transit, and less oriented toward private auto, intensification is being practiced throughout the Greater Golden Horseshoe. York Region, an outer suburban municipality undergoing intensification, has been selected for analysis. This report studies TTS (Transportation Tomorrow Survey) data using multiple linear regression, as well as comparative analysis to evaluate the effect an increase in density has upon transit modal split. Findings align strongly with reviewed literature. Findings are that while density and transit mode split are positively statistically correlated, the impact density is estimated to have on transit mode split is minimal. This suggests intensifying the outer suburbs may have the reverse effect of increasing auto traffic at the expense of small increases in transit mode split. A series of recommendations regarding transportation policies for outer suburban municipalities are then provided to coexist with intensification policies.

The intensification of the outer suburbs and the impact on travel behaviour: an analysis of York Region

In an effort to retrofit outer suburban municipalities to be more supportive of public transit, and less oriented toward private auto, intensification is being practiced throughout the Greater Golden Horseshoe. York Region, an outer suburban municipality undergoing intensification, has been selected for analysis. This report studies TTS (Transportation Tomorrow Survey) data using multiple linear regression, as well as comparative analysis to evaluate the effect an increase in density has upon transit modal split. Findings align strongly with reviewed literature. Findings are that while density and transit mode split are positively statistically correlated, the impact density is estimated to have on transit mode split is minimal. This suggests intensifying the outer suburbs may have the reverse effect of increasing auto traffic at the expense of small increases in transit mode split. A series of recommendations regarding transportation policies for outer suburban municipalities are then provided to coexist with intensification policies.

A data-driven complex network approach for planning sustainable and inclusive urban mobility hubs and services

New mobility services that facilitate multimodal options are important for strategic urban transport systems planning. Part of this strategy is municipal investment in urban mobility hubs to increase access to mobility services. We present a new evaluation framework and algorthim to locate and assess the sustainability and equity impacts of hubs in cities. Scenarios are used to evaluate hub investment strategies in different cities that prioritize (1) current mode split, (2) high transit capacity, and (3) multimodal services. From an equity perspective, high transit capacity and multimodal hub strategies include more low-income areas than current mode split, which covers middle-income areas most. Travel times to access the nearest hub in Portland by low-income households is ∼20–40 min compared to high-income households requiring ∼25–30 min. Seattle and Vancouver perform better requiring ∼15–20 min for low-income compared to ∼25–35 min for high-income households. Multimodal hubs are the most efficient requiring ∼15–20 minutes to reach compared to ∼15–30 minutes for high capacity and current mode split scenarios. From a sustainability perspective, ∼10%–50% of the population cannot reach a hub within 30 minutes by public transit compared to <10% by car, and travel time to reach the nearest hub in all three cities by car is <20 min compared to ∼20–40 min by public transit. Between all cities, low-income households representing ∼2%–15% of the total population have no access to a hub by public transit within 30 min compared to high-income households representing ∼1%–3% of the total population. Only in Portland are there low-income households not able to reach a hub by car, and in each city, all high-income households can reach at least one hub by car within 30 min. Our results show how municipalities can strategically invest in public transit and multimodal options to increase the frequency, quality, and overall mobility for low- and medium-income households and improve access to essential amenities for more vulnerable citizens. Municipalities can use our hub evaluation framework to explore alternative transport investment scenarios and spatially locate urban hubs to meet future travel demand, increase adoption of multimodal services, and improve equitable access for all citizens.

Sensitivity Analysis of Single-Drive, 3-axis MEMS Gyroscope Using COMSOL Multiphysics

In this paper, a COMSOL Multiphysics-based methodology is presented for evaluation of the microelectromechanical systems (MEMS) gyroscope. The established finite element analysis (FEA) model was successfully validated through a comparison with analytical and Matlab/Simulink analysis results. A simplified single-drive, 3-axis MEMS gyroscope was analyzed using a mode split approach, having a drive resonant frequency of 24,918 Hz, with the x-sense, y-sense, and z-sense being 25,625, 25,886, and 25,806 Hz, respectively. Drive-mode analysis was carried out and a maximum drive-displacement of 4.0 μm was computed for a 0.378 μN harmonic drive force. Mechanical sensitivity was computed at 2000 degrees per second (dps) input angular rate while the scale factor for roll, pitch, and yaw was computed to be 0.014, 0.011, and 0.013 nm/dps, respectively.